The state of Hawaii has some incredible trails. You can put on your hiking shoes and visit gorgeous waterfalls bathed in rainbows. You can wander along beautiful beaches. You can hike through volcano tubes to volcano summits, or just wander around towns looking for the perfect shave ice. (You should try a lot of them to make this experiment worth it… for science.) However, if you want to do a surprising hike in Hawaii, there is a singular experience you cannot miss. On the Big Island, you can hike up to the only alpine lake in the state of Hawaii, which also happens to be one of the highest lakes in the entire United States of America. This unusual place is Lake Waiau on the Mauna Kea volcano, not that far from the summit.