Jammed: Overcrowding at the world's most popular tourism sites

This past Christmas, Disneyland and Walt Disney World's Magic Kingdom temporarily reached maximum capacity and were forced to close their gates and turn away guests until the crowds thinned. And while these highly popular theme parks both routinely rank among the 20 most visited sites in the world, they are hardly the only destinations grappling with the challenge of how to balance a surging global traveling population with the finite capacity that tourist hot spots can sustain.