Belize’s Great Blue Hole is a world-famous marine sinkhole, over 400 feet deep and nearly 1,000 feet wide. Located within the Lighthouse Reef Atoll, it’s part of a UNESCO World Heritage Site and a top destination for divers, snorkelers, and photographers. From Belize City, you can reach it by a full-day boat tour for reef adventures or by a 1-hour scenic flight for breathtaking aerial views. However you go, the Great Blue Hole is a must-see natural wonder.