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.

This Mesoamerican archaeological site was an important regional center and capital of the Toltec Empire between the fall of Teotihuacan and the rise of Tenochtitlan. Tula contains many impressive sights, including the basalt columns carved in the shape of Toltec warriors on the Pyramid of Quetzalcoatl.

Sajama National Park lies in western Bolivia near the border with Chile, within the highlands of the Oruro Department. It protects a broad landscape of volcanoes, high-altitude grasslands, wetlands, volcanic formations, and native queñua forests. The park is centered on Nevado Sajama, Bolivia’s highest mountain, whose snow-covered summit rises above the surrounding Altiplano.

Originating as a tiny fishing village in 1038, modern Kehl has become an important link between Germany and France. Rhine River cruises most often use Kehl as their gateway to the much larger and better-known Strasbourg. The savvy traveler, though, might choose to skip the jaunt across the river and enjoy many similar sights, shopping and cuisine as those offered in the teeming French city.

Pitlochry, a charming town in the heart of the Scottish Highlands, is celebrated for its Victorian architecture, scenic surroundings, and welcoming atmosphere.