Adjacent islands are extensions of the mountain ranges of the main island, which dip into the sea and emerge again as smaller islands. The volcanic islands of Vieques and Culebra are extensions of the geological system of the Central Cordillera. They began forming 100,000,000 years ago with a series of underground movements that included the tectonic plate pressure beneath the Caribbean plate and the shifting toward the east (from Vieques, PR website). Today, Isla Vieques, with its rolling hills and breathtaking coastlines, is one of the most beautiful islands in the Caribbean. [links]