Maybe on Oregon coastline, too? Glass Beach is a beach in MacKerricher State Park near Fort Bragg, California that is abundant in sea glass created from years of dumping garbage into an area of coastline near the northern part of the town.
Explore the ancient caves of Hang Son Doong, Vietnam. Hang Son Doong is one of the largest caves in the world and features a fast-flowing underground river. For spelunkers, exploring Hang Son Doong is the equivalent of scaling Mount Everest.