The city of Las Vegas, which sits in a basin, is visible in the center of this low-oblique, north-looking photograph. The drainage into this basin can be identified northwest of the city (whitish area between two mountain ranges). During occasional heavy rainfall, downtown streets flood—especially the street know as the Strip, where most of the large hotels and gambling casinos are located. Las Vegas is famous worldwide as a tourist and recreation area and has expanded greatly in the last few decades with the growth of tourism. New residential areas appear west and northwest of the city as expansion continues. The dark blue waters of Lake Mead, one of the largest reservoirs in the United States, are seen east of Las Vegas. Hoover Dam, a white dot at the southern end of the lake, shows where the Colorado River continues its southward flow toward the Gulf of California. Between Lake Mead and Las Vegas are parallel ridges (reddish-white) of the Valley of Fire State Park. Visible are the reddish mountains of Red Rock Canyon west of the city and the dark, forested Spring Mountains to the northwest.