Matthew Lavian / Marist College via AP

A giant foam head floats on the Hudson River in Poughkeepsie, N.Y., on Monday, April 22.

A huge foam and fiberglass head was discovered floating in New York's Hudson River by a college crew team earlier this week, and days later nobody knows where it came from.

The head, which is at least 7 feet tall and 5 feet wide, was found Monday morning by the Marist College men's crew team. 

"The coach, who is in a motorboat, took a quick spin out and investigated it, and was as baffled as anyone by what he saw," said Greg Cannon, spokesman for Marist College. "But because it was a navigation hazard, he felt it was his duty to haul it in. It took about 10 members of his team to haul it in." 

Because it was waterlogged, it weighed "at least a couple hundred pounds," he said. The head -- which has a foam core but is covered in a fiberglass shell and has metal rods in it -- has had a home in front of the Marist boathouse since it was dragged from the water.

Tyler Sawyer / Marist College via AP

Members of the Marist college crew team stand by a giant foam head found floating in the Hudson River in Poughkeepsie, N.Y., on Monday, April 22.

It's attracted lots of visitors and theories as to where it came from, including one suggestion that it came from a Mardi Gras parade and floated to Marist, which is located in Poughkeepsie, N.Y., overlooking the Hudson. But there have been no claims of ownership.

"It's not like someone just built it as a hobby, I don't think. It was definitely for an art installation, or a theater project," Cannon said.

The head, which has a gray shell and fleshy tones underneath, is missing some chunks, including its nose.

"It's kind of like a lost puppy," Cannon said. "If the owner shows up, we'll certainly return it, but I think the people will be sad to see it go."

Charles Dharapak / AP

President Barack Obama stands with, from second from left, former presidents George W. Bush, Bill Clinton, George H.W. Bush, and Jimmy Carter at the dedication of the George W. Bush Presidential Library on the campus of Southern Methodist University in Dallas on April 25.

By Tom Curry, National Affairs Writer, NBC News

Giving a broad-strokes defense of his eight years in the White House, former president George W. Bush celebrated the dedication of his the Bush Presidential Library and Museum in Dallas on Thursday. In the audience were the nation’s three other former living presidents – George H.W. Bush, Bill Clinton, Jimmy Carter – as well as current commander in chief Barack Obama.  Read full story

David J. Phillip / AP

From left, first lady Michelle Obama, former first lady Laura Bush, former first lady Hillary Clinton, former first lady Barbara Bush and former first lady Rosalynn Carter arrive for the dedication of the George W. Bush Presidential Library.

Charles Dharapak / AP

Former Vice President Dick Cheney, center, shakes hands with former British Prime Minister Tony Blair during the dedication of the George W. Bush Presidential Library. Former President George W. Bush's daughter Jenna Bush Hager is at right.

Brendan Smialowski / AFP - Getty Images

Former President George H. W. Bush, left, former President George W. Bush and Laura Bush listen during a dedication ceremony at the George W. Bush Library.

Jewel Samad / AFP - Getty Images

President Barack Obama, left, and former presidents, from left, George W. Bush, Bill Clinton, George H.W. Bush and Jimmy Carter arrive on stage for the George W. Bush Presidential Library dedication.

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Michael Chang / Getty Images

The sun rises the morning that the live oak trees will be cut down by crews from the Asplundh tree service on April 23, 2013 at Toomer's Corner in Auburn, Alabama.

Michael Chang / Getty Images

A member of the Asplundh tree service helps cut down an oak tree on April 23, at Toomer's Corner in Auburn, Alabama.

Dave Martin / AP

Auburn University employee Dinah Decker, center, wipes tears from eyes as she watches as city workers cut down the poisoned oak trees at Toomer's Corner at the entrance to Auburn University in Auburn, Ala., on April 23.

Auburn University removed the dying oaks at Toomer's Corner Tuesday morning, after they were poisoned by a rival fan shortly following the 2010 Iron Bowl. Harvey Updyke Jr. is serving a jail term after pleading guilty to spiking the oaks with a powerful herbicide, and experts say they can't be saved. Workers used chainsaws and heavy equipment to remove what's left of the once-lush hardwoods at Toomer's Corner. Auburn fans traditionally roll the trees with toilet paper after a big victory, and tens of thousands rolled the trees after the spring football game last Saturday.

-- The Associated Press

Dave Martin / AP, file

Fans roll the poisoned oak trees at Toomer's Corner one final time following Auburn's A-Day spring NCAA college football game at Jordan-Hare Stadium in Auburn, Ala., on April 20, 2013. The tradition of "rolling" the trees at Toomer's Corner following a win by the football team is coming to an end.

Dave Martin / AP

A photographer uses his cell phone to photograph the oak trees at Toomer's Corner at the entrance to Auburn University in Auburn, Ala., Tuesday, April 23, 2013. City workers cut down the poisoned oak trees at the entrance to Auburn University.

Jianan Yu / Reuters

Tents outside a hospital light up at night after Saturday's earthquake hit Lushan county, Ya'an, Sichuan province, on April 22. Hundreds of survivors of an earthquake that killed nearly 200 people in southwest China pushed into traffic on a main road on Monday, waving protest signs, demanding help and shouting at police. The Chinese characters on the tent read "Disaster relief".

AFP - Getty Images

Medical personnel work with a flashlight in a temporary settlement in Lingguan Middle School in Baoxing county of Yaan, southwest China's Sichuan province, on April 21.

How Hwee Young / EPA

Chinese soldiers cook breakfast in a rescue camp in Taiping town, Lushan County, Sichuan Province, China, on April 23.

How Hwee Young / EPA

Residents gather around a fire outside damaged homes in Taiping town, Lushan County, Sichuan Province, China, on April 23.

AFP - Getty Images

People gather at a power supply station in a temporary settlement in Lingguan Middle School in Baoxing county of Yaan, southwest China's Sichuan province, on April 21.

AFP - Getty Images

A man works in a shed at a temporary settlement in Lingguan Middle School in Baoxing county of Yaan, southwest China's Sichuan province, on April 21.

AFP - Getty Images

People fall asleep at the power supply station at a temporary settlement in Lingguan Middle School in Baoxing county of Yaan, southwest China's Sichuan province on April 22.

Related:

• PHOTOS: Earthquake in China
• Frustration rises from rubble following China's deadly quake
• Residents and rescuers find nourishment after powerful earthquake in China

FBI.gov

FBI.gov

NBC News reports

The FBI has released video and photos of two "armed and dangerous" suspects in the Boston Marathon bombing and appealed for the public's help in identifying them.

The images show two men in baseball caps. One of them was seen putting down a black backpack at the site of the second blast in Monday's attack. Both were seen walking together through the crowd.

"Somebody out there knows these individuals…though it may be difficult, the nation is counting on those with information to come forward and provide it to us,” Boston FBI Special Agent in Charge Richard DesLauriers said at a Thursday briefing.

Also on PhotoBlog:

• Life disrupted: Eerie scenes after Boston Marathon bombings
• Marathon's deadly moments captured from office building above finish line
• Anatomy of a bombing: Photos show battery, wires used in device

FBI.gov

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Laura Leon / AP

A mare, a ''Pura Raza Espanola," or Pure Spanish Breed, runs next to the stable at "La Yeguada de Cuatro Vientos" ranch in Almonte, in southern Spain's Andalusia region on April 8. Barring an unlikely reprieve, the purebreds at this ranch will be turned into horse meat for export in the coming months.

Laura Leon / AP

A Pure Spanish Breed horse rears up inside a stable at La Yeguada de la Nobleza ranch in Almonte, Andalusia, Spain.

By Alan Clendenning, The Associated Press

The southern Spanish region of Andalusia, famed for flamenco and Moorish castles, is also home to a legendary breed of horses that carried conquistadors into battle in the Americas, featured in Hollywood epics and more recently became trophy acquisitions for Spaniards during a giddy economic boom.

On his grassy ranch in the territory's heartland, 73-year-old Francisco Mesa breeds these ''Pura Raza Espanola" - Pure Spanish Breed - horses with a passion that comes from years of pampering the elegant beasts known for their intelligence and affection for humans. He enters a muddy pen and is immediately surrounded by mares and foals who nuzzle him with tenderness, oblivious of their almost certain fate: the slaughterhouse. 

Barring an unlikely reprieve, Mesa' purebreds will be turned into horse meat for export come July. They are victims of a wrenching economic downturn that has wiped out fortunes, turned housing developments into ghost towns and left more than a quarter of the population out of work. Read more here 

Laura Leon / AP

Butcher Manuel Delgado prepares a piece of a ''Pura Raza Espanola,'' Pure Spanish Breed horse meat, at a horse meat butcher in Camas, Spain.

Laura Leon / AP

Breeder Francisco Mesa places his hand on the back of one of his Pure Spanish Breed horses at "La Yeguada de la Nobleza" ranch on April 8.

Laura Leon / AP

Sculptures of horse heads decorate the main entrance of "La Yeguada de Cuatro Vientos" ranch, belonging to breeder Francisco Jose Rodriguez, in Almonte, Andalusia, Spain, on April 8.

Laura Leon / AP

Pure Spanish Breed mares, belonging to breeder Francisco Jose Rodriguez, walk in a field at "La Yeguada de Cuatro Vientos" ranch in Almonte, Andalusia, Spain, on April 2.

Laura Leon / AP

A Pure Spanish Breed horse belonging to breeder Francisco Mesa at "La Yeguada de la Nobleza" in Almonte, Andalusia, Spain, on April 8.

Previously on PhotoBlog:

• Riders jump horses over flames to honor patron saint of animals in Spain
• Just keep swimming, Shoshoni: A horse gets his exercise in Scotland's largest loch
• Leading a horse to water in Gaza

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Elise Amendola / AP

Two men in hazardous materials suits put numbers on the shattered glass and debris as they investigate the scene at the first bombing on Boylston Street in Boston on April 16, 2013 near the finish line of the 2013 Boston Marathon.

From a blood-covered zipper pull to a dented blue-and-silver battery, the Boston Marathon bombing site has yielded important forensic evidence that authorities will use to profile and track suspects.

New photos of the crime scene where white-suited FBI specialists are gathering evidence are testament to the power of the two bombs, which twisted a metal pressure cooker apart and sprayed debris on rooftops.

The force of Monday’s blast killed three people and tore off the limbs of other victims, but dozens of clues were left behind.

Joint Terrorism Task Force of Boston via Reuters

Boston Marathon bomb scene pictures taken by investigators show the remains of an explosive device. The photos were produced by the Joint Terrorism Task Force of Boston, provided to Reuters April 16, 2013 by a U.S. government official who declined to be identified.

There are orange and black wires marked with manufacturer details, half-inch nails known as brads, a made-in-China battery emblazoned “3000,” a green circuit board less than 2-inches long, and a shredded nylon bag.

Joint Terrorism Task Force of Boston via Reuters

Separately, they look like pieces of junk you might find in a work shed. Together, they are road map to terror and tragedy.

Investigators, led by the FBI through the Joint Terrorism Task Force, are already analyzing each fragment. No detail – not even the insignia on the zipper pull that could be from the bomber’s bag – will escape attention.

Authorities will try to figure out where the components were bought and compare them to devices used in other attacks. Ultimately, they hope the clues will lead them to the person or group that built, planted and detonated the bombs at the finish line of the iconic race.

One thing is already clear.

“They functioned as designed,” one official told NBC News.

“It appeared to be built from scratch but with a sophisticated triggering mechanism. And frankly, at the end of the day, all bombs are crude devices, and it is the way they are triggered that can be sophisticated.”  

Joint Terrorism Task Force of Boston via Reuters

Joint Terrorism Task Force of Boston via Reuters

Joint Terrorism Task Force of Boston via Reuters

Joint Terrorism Task Force of Boston via Reuters

Joint Terrorism Task Force of Boston via Reuters

Joint Terrorism Task Force of Boston via Reuters

Joint Terrorism Task Force of Boston via Reuters

Related:

• Life disrupted: Eerie scenes after Boston Marathon bombings
• Marathon's deadly moments captured from office building above finish line
• Video -- Former ATF agent: ‘These are hellish’ devices

Spencer Platt / Getty Images

The unfinished meals of fleeing customers are left on tables at an outdoor restaurant near the scene of a twin bombing at the Boston Marathon on April 16, 2013 in Boston, Mass. The twin bombings, which occurred near the marathon finish line, resulted in the deaths of three people while hospitalizing at least 128. The bombings at the 116-year-old Boston race, resulted in heightened security across the nation with cancellations of many professional sporting events as authorities search for a motive to the violence.

Justin Lane / EPA

Bags of people's belongings gathered not far from the finish line of the Boston Marathon as an investigation continues into dual bombings at the site, in Boston April 16.

While there have been many moving photos of the bombings at the Boston Marathon, these quiet, empty moments are powerful in their own way. The plates full of uneaten food at an abandoned restaurant suggest the chaos immediately following the explosions, causing people to flee leaving unfinished drinks and unpaid bills. Yellow bags full of runners’ personal belongings, intended to be picked up after crossing the finish line, instead evoke unrealized dreams of completing a marathon. The silver thermal blankets that so often are worn proudly following a race, yesterday served a much different purpose and blanketed injured runners.

Related:

• Marathon's deadly moments captured from office building above finish line
• Martin Richard, 8, killed in Boston Marathon blast
• The man in the hat at Boston Marathon finish line: Carlos Arredondo didn't set out to be hero

Spencer Platt / Getty Images

Unused thermal blankets for marathon participants are piled near the scene of a twin bombing at the Boston Marathon on April 16, in Boston.

Jessica Rinaldi / Reuters

Blood in seen on the sidewalk in front of a candy store advertising a Marathon Monday sale a day after two explosions at the Boston Marathon in Boston, on April 16.

Brian Snyder / Reuters

Two police officers walk down Boylston Street, away from the finish line of the Boston Marathon in Boston on April 16.

Slideshow: Aftermath and reaction following Boston bombings

Shannon Stapleton / Reuters

Heightened security, empty streets, and memorials mark the the day after the Boston Marathon bombings.

Launch slideshow