Plunge into this deep blue hole and you'll discover imposing ancient stalactites (calcium deposits resembling icicles) and coral fringe. Declared a UNESCO World Heritage Site in 1996 — along with six other areas surrounding Belize's barrier reef — the Great Blue Hole remains one of the world's most distinguished scuba sites. Created approximately 10,000 years ago after a cave roof crumbled in, this blue channel contains underwater tunnels, caverns and rock formations.

You'll likely spot marine life lining the coral wall at the surface of the hole. As you descend about 410 feet below sea level, you'll discover the stalactites, but it's unlikely you'll encounter many underwater creatures (except the occasional shark!). Even if you're not a diver, recent visitors recommended snorkeling around the hole and the nearby reefs. Make sure to visit in the dry season, with ideal weather conditions most likely in April and May.

The Great Blue Hole is located about 43 miles off the coast of Belize along the Lighthouse Reef Atoll. You can visit the Great Blue Hole with a number of dive services that operate out of Belize City, San Pedro and Caye Caulker. In addition to operator fees, be prepared to pay an extra $40 to dive and snorkel at the Great Blue Hole.