Between Morocco and Spain sits the tiny British territory of Gibraltar. Construction of the airport dates back to World War II, and it continues to serve as a base for the United Kingdom's Royal Air Force, though commercial flights land on a daily basis.
Why It's Unique:
Winston Churchill Avenue, Gibraltar's busiest road, cuts directly across the runway. Railroad-style crossing gates hold cars back every time a plane lands or departs. "There's essentially a mountain on one side of the island and a town on the other," Schreckengast says. "The runway goes from side to side on the island because it's the only flat space there, so it's the best they can do. It's a fairly safe operation as far as keeping people away," he says, "It just happens to be the best place to land, so sometimes it's a road and sometimes it's a runway."