Kimimasa Mayama / EPA

A Moon Jellyfish swims in the water at a Tokyo aquarium, Japan, May 3. The Golden Week, a week-long national holiday period in Japan, takes place from April 28 to May 6.

Kimimasa Mayama / EPA

A mother and her baby watch Moon Jellyfish swimming in the water at a Tokyo aquarium, Japan, May 3.

Kimimasa Mayama / EPA

Moon Jellyfish swim in the water at a Tokyo aquarium, Japan, May 3.

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Sarosh Jacob

Sarosh Jacob

Sarosh Jacob

Vicky Floresca

Sarosh Jacob

Sarosh Jacob, an msnbc.com reader, shared with us his experience at Jellyfish Lake in Palau.

This lake is unique in that it is a remnant of the ice age and these jellyfish only exist in Palau and nowhere else. Thousands of years ago the jellyfish became trapped in this lake and with no predators they evolved into a new species that no longer have harmful stings. This allows you to safely swim with tens of thousands of them! It was one of the most incredible experiences in my life.
I first heard about the lake in a BBC documentary called South Pacific. As soon as I saw what it looked like I knew I would go there one day to experience it for myself. When I arrived at the island I had to hike a pretty steep and rocky trail to get to the lake. My camera with the underwater housing is very heavy so luckily I brought a backpack to carry it because I don't think I could have managed up the steep trail trying to hold it in my hand. When I entered the lake I was not sure what to expect. At first I saw nothing but water, as I continued to swim further out I saw one jellyfish and I remember being excited by that. Then I swam some more and saw 10 or 12 jellyfish, then a hundred and all of the sudden I found myself surrounded by thousands of jellyfish! It was truly a surreal moment. In all my years of diving I had never experienced anything quite like it. A lot of people have been asking me if I was stung by the jellyfish. I was perfectly fine; from what they told me in Palau, the jellyfish in this particular lake are harmless as their stingers are not powerful enough to affect people.  Palau truly is a special place.

More at Jacob's website: www.saroshjacob.com