"A geologic centerpiece of the park, this large caldera is a supervolcano underlying much of the thermal activity in the region and helps explain the area’s abundant geysers, hot springs and other geothermal features." - Evie Carrick Evie Carrick Evie Carrick is a writer and editor who’s lived in five countries and visited well over 50. She now splits her time between Colorado and Paris, ensuring she doesn't have to live without skiing or L'As du Fallafel. Travel + Leisure Editorial Guidelines