Arizona is home to active volcanic areas, some have only just erupted 1,000 years ago! You can even visit these volcanic areas. Within the San Francisco volcanic field located in Flagstaff Arizona, lies the Sunset Crater. When the last volcanic eruption occurred, a 6.5 mile crevice opened and created a wall of fire, made from multiple lava spouts. At Sunset Crater you can find “Corn Rocks” that are impressions of maize cobs from the Native Americans. It is said that the Native Americans placed the cobs in/near the lava to intentionally create these.
Another volcanic site to see is the Merriam Crater and Grand Falls. 20,000 years ago the volcano erupted and sent lava flowing about 6 miles towards the Little Colorado River Canyon. Within the canyon lava spilled into the river blocking it. It then began to flow up and down the canyon for 9 miles. The lava filled The Grand Falls Canyon and overflowed another half mile past the width of the canyon.