Hidden in the northern region of Costa Rica, the Celeste River (Río Celeste) winds through Tenorio Volcano National Park with a color so vivid it seems unreal. The river’s striking turquoise hue is caused by a natural chemical reaction between two mineral-rich streams, Quebrada Agria and Río Buena Vista, which merge at a point known as "El Teñidero." This one-of-a-kind phenomenon creates the illusion that the water has been dyed blue, even though no pigments are present.

Stromboli is a small volcanic island in the Tyrrhenian Sea, just off the north coast of Sicily. Referred to by some as the "Lighthouse of the Mediterranean," Stromboli is in a constant state of mild volcanic activity, so don't venture out on a hike without an experienced guide.

Eminently livable and a pleasure to visit, Zurich is Switzerland's largest and most affluent city. This Central European metropolis is an engine of finance and banking, and has much to offer to visitors. There are numerous art museums, fine chocolate stores, and boundless luxury shopping opportunities.

In Cyprus, travelers are immersed in a culture that draws on Europe, the Middle East, and 9000 years of constant invasion. Crusader castles rub shoulders with ancient vineyards, frescoed monasteries overlook citrus orchards, and sandy, sun-soaked feet tread Roman mosaic floors.

Marseilles is an enticing port city known for its delectable seafood, breathtaking views of the Mediterranean, and diverse melting pot of cultures.