Kos, an enchanting island in Greece’s Dodecanese archipelago, is a gem steeped in both history and natural beauty. Known as the birthplace of Hippocrates, the father of modern medicine, Kos is home to the ancient Asclepeion, a healing temple where Hippocrates taught his students. Visitors can wander through the well-preserved ruins and enjoy sweeping views over the island and the Aegean Sea.

Nestled on the southern shore of the Firth of Forth, South Queensferry is a picturesque town in Scotland that offers a delightful blend of historical charm and stunning natural beauty.

San Juan, Puerto Rico’s capital, is a city where cobblestone streets lead to centuries-old forts and pastel-colored buildings overlook the Atlantic. The district of Old San Juan is a UNESCO World Heritage Site, known for its Spanish colonial architecture and thick stone walls that once defended the city from pirates and naval attacks. The city hosts regular events such as La Campechada, which celebrates Puerto Rican art and literature with live performances and open-air exhibits.

Coursing through 10 countries, the Danube is the second-longest river in Europe. This waterway, lined with fortresses and castles, rises in Germany's Black Forest and runs for 1,770 miles to the Black Sea. The Danube is an essential commercial thoroughfare for central and southeastern Europe, and several river cruise companies sail vessels on it year-round. Destinations along this river include Vienna, Budapest, Passau and Bratislava.

A relatively recent addition to Costa Rica's list of national parks is Tenorio Volcano National Park, home to its namesake Tenorio Volcano as well as its taller sister, Miravalles Volcano, also the highest mountain in the Guanacaste Mountains.