The tallest building in the world casts a long shadow on downtown Dubai, as seen in this picture from the GeoEye-1 satellite. But this is no Tower of Babel: Its 2,717-foot height comes nowhere close to reaching the satellite's 423-mile-high orbit. The $1.5 billion Burj Khalifa building made its Dubai debut in January, and recently served as the setting for scenes filmed with Tom Cruise for the upcoming movie "Mission: Impossible 4." Check out our story about the building's opening for additional background and visual perspectives.

It's particularly apt that Burj Khalifa figures in the fourth "Mission: Impossible" movie, because GeoEye's view serves as the visual treat behind Door No. 4 in our Cosmic Log Space Advent Calendar. Check back with Cosmic Log or Photoblog every day until Christmas for another view of Earth from space.

Here are some links to help you catch up with the calendar entries so far, and dig into additional treats from the holiday season's other space-themed Web calendars:

• From Day 1: The Cosmic Log Advent Calendar so far
• Door 2 for Dec. 2: 'Alien' lake seen from space
• Door 3 for Dec. 3: Egypt's river of light
• The Big Picture at Boston.com: Hubble Advent calendar
• Planetary Society: Solar system Advent calendar
• Zooniverse Advent calendar