Exclusive residential underwater villas at The World Islands' Monaco Island, are to be previewed, at an invitation-only event, strictly for investors and end-users.

"Agents please excuse, as this is a private event for investors and end-users only," an emailed invitation says.

The three-level, 1,700 square-foot villas, are being built on Monaco Island, as part of The Heart of Europe (THOE) project, and will be the first residential properties to be built anywhere on the World Islands. The extraordinary designs involve the lowest level of the villa sitting below the water, with a floating sun deck surrounded on three sides by water. The European Islands also will include an exclusive marina and pool, while guests are expected to arrive by private luxury yachts, sea planes or helicopters.