"The Great Blue Hole is a natural sinkhole that measures roughly 1,000 feet across and 400 feet deep. It is part of the Belize Barrier Reef Reserve System, a UNESCO World Heritage Site. Known for its deep navy blue center, it is a prominent diving site made famous by Jacques Cousteau. Visitors can access it via boat or helicopter from Belize's barrier islands. The site is ideal for advanced divers, offering a chance to explore stalactites, stalagmites, and marine life. Helicopter tours are available for those who prefer not to dive." - Travel + Leisure Editors