The American Southwest? No, this is Hawaii.
Waimea Canyon is on the island of Kauai, and looks like a tropical version of the Grand Canyon. In fact, it is often referred to as "The Grand Canyon of the Pacific." It is approximately ten miles long and 3000 feet deep, and has been carved by runoff from the island's central peak, Mount Wai'ale'ale, one of the wettest places on earth. It averages 452 inches of rain a year, and the record is 683 inches in 1982