Strong hikers can attempt to scale the Sierra Negra volcano, which boasts the world's second largest volcanic caldera. The hike can take visitors to the rim of the imposing 6-mile wide crater and over alien volcanic fields and landscapes, giving them the opportunity to admire strange and interesting geological features and to enjoy the views of volcanoes on other islands from a distance. Visiting the volcano can mean a total of 6 hours hiking, though, so make sure you are prepared for such an adventure.

Do you want to learn more about the dark past of this area, going back to its communist past? Then, pay a visit to 10-Z, code name for the top secret nuclear bunker situated right in the heart of Brno. This is definitely a unique experience.

Seville Cathedral is the third-largest cathedral in Europe. Originally built as a mosque in the 12th-century, the 100-metre- high minaret is now the Giralda clock tower. Christopher Columbus is buried inside the cathedral.

A 20-minute boat ride from Cancún lies the small island of Isla Mujeres with its laid-back Caribbean ambiance, tiny streets lined with stalls, and street cafés in pastel-colored houses. Golf carts and mopeds dominate the streets, and although the island is only 5 miles long and half a mile wide, it still offers plenty of things to do and see. Everything from a beautiful palm-fringed white beach on the north coast to a dramatic rocky shoreline on the eastern side to a sea turtle sanctuary and the remains of a Mayan temple at the southern tip. If you're into adventure, then you should visit the Garrafon Reef Park & Beach Club, where you can go zip-lining, snorkeling, and kayaking. Lastly, a must-visit for nature and wildlife lovers is a tour to Isla Contoy, a nature reserve only inhabited by a few biologists and restricted to 200 visitors per day.