In the glittering Mediterranean Sea sits a diamond-shaped island shrouded in secrecy: Montecristo. It opens twice a year to the public...but only for a lucky few. The beautiful island of Montecristo is the fourth largest island of the Tuscan Archipelago (a chain of islands west of Tuscany, Italy including Elba and Capraia) and is about four square miles in size. It has a colorful history full of monks, pirates and saints. The island also serves as the supposed site of a buried treasure in the classic novel, "The Count of Monte Cristo" by Alexandre Dumas. But what makes it so amazing is that the 5 million-year-old island is virtually untouched, preserving its rich biodiversity; it's home to flora, fauna (like wild goats) and marine life.

Wild goats (Capra aegagrus hircus), Montecristo island, Tuscan Archipelago National Park, Tuscany, Italy. DEA | S. VANNINI | Getty Images

It's also extremely exclusive: Only four people live on the island — two groundskeepers and two rotating members of its military police force, according to Lonely Planet. And the island only began granting access to visitors for the first time in 2008. Now outsiders are only allowed just five months a year, and even then, space is extremely limited. Visitors are welcomed on day passes (which reportedly cost around $60) from Aug. 31 to Oct. 31 and from April 1 to July 5. In an effort to protect Montecristo's environment, a maximum of 1,000 visitors are allowed to visit the island a year (roughly 50 visitors are permitted a day) with 600 spots reserved for students and 400 for adults. Preference reportedly goes to scientific teams and educational trips. This type of adventure isn't for procrastinators or solo travelers, either: You'll need to plan ahead and get a big group together in order to make this a successful getaway.

Cala Maestra, Montecristo island, Tuscan Archipelago National Park, Tuscany, Italy. DEA | S. VANNINI | Getty Images

"The island is not served by scheduled ferries and therefore those who get authorization to visit must independently find a boat suitable to cover the approximately 40 nautical miles from the mainland," Aurora Ciardelli, a spokeswoman for the Tuscan Archipelago's National Park, told The Local.