Did you know... the coral reef inside the Giant Ocean Tank is hollow?! 🤯 While it looks like a thriving coral ecosystem, the reef structure is actually made of fiberglass and rubber that is supported by concrete slabs, columns, and even plumbing to help create natural water flow. The reef has two access hatches (one tucked under the sand up top and one hidden in the cave below), which divers use several times a year to climb inside the reef for inspections and maintenance. Yep, they actually go