Houston often appears to be a ghost town, in part due to its nearly complete lack (until recently) of downtown draws but also because its hot and humid weather (which locals oft refer to as "super-summer"). Below the city streets is an underground city of restaurants, businesses, and shops along a 6.3-mile pedestrian tunnel system that connects more than 80 downtown buildings. Photo 7 of 17 in Houston, Texas

Houston, Texas

7 of 17

Houston often appears to be a ghost town, in part due to its nearly complete lack (until recently) of downtown draws but also because its hot and humid weather (which locals oft refer to as "super-summer"). Below the city streets is an underground city of restaurants, businesses, and shops along a 6.3-mile pedestrian tunnel system that connects more than 80 downtown buildings.