The observation deck on the 124th floor of Dubai's Burj Khalifa, the world's tallest building that just opened last month, has been closed due to faulty elevators. On Saturday, some 15 people were trapped in an elevator after a small explosion. The elevator car was trapped between floors, and rescue crews had to hoist a ladder into the elevator shaft to get passengers out. At least it didn't require helicopters, like the recent rescue efforts at Machu Picchu to evacuate thousands of tourists, but it got us thinking about what the two closed sites having in common. One's a crumbly ancient city in South America, and the other's a really tall building in a crumbling, post modern Middle Eastern city that will make for interesting ruins someday. Let's compare.

The site: The observation deck of the Burj Khalifa, the world's tallest building Location: Dubai Reasons given for closure: "issues with the power supply" What That Means: Getting tourists to an observation deck 124 floors up isn't easy Dramatic event proceeding closure: A loud noise, dust seeping out of the cracks of one of the elevator doors. Fifteen people were stuck in one elevator, while another 60 people already on the deck had to be taken down in a freight elevator. Estimated reopening: Sunday

The site: Machu Picchu, the ancient city of the Incas Location: Peru Reasons given for closure: Torrential rains damaged the railways that are the only transportation in and out of the area around the site. What That Means: Getting tourists to isolated ruins atop a jungle-covered mountain is hard. Dramatic event proceeding closure: Deadly rains and mudslides, days of helicopter evacuations of thousands of tourists and residents Estimated reopening: The site itself could reopen for hikers in less than three weeks, but it could be months before railways into and out of the areas are repaired.