This annual issue, leading up to the 500th anniversary of Columbus's voyage to the New World, had as its design the Grand Canyon, a spectacular gorge carved by the Colorado River into the rocks. Total length of the canyon is 217 miles (349 km), from the Little Colorado River to Lake Mead, of which 105 miles (169 km) is in Grand Canyon National Park. In places the canyon is more than a mile deep. Garcia Lopez de Cardenas, a Spanish explorer, discovered the canyon in 1540. Systematic exploration did not begin until 1850. John Wesley Powell was in 1869 the first to travel through the canyon by boat. The national park, created in 1919, has an area of 673,575 acres. Grand Canyon National Monument, created in 1932, covers 198,280 acres.