Heidelberg City, Germany. Travel Guide, Tourism. Surrounded by forest, Germany's oldest and most famous university town is renowned for its baroque Altstadt, beautiful riverside setting and evocative half-ruined hilltop castle, which draw 11.9 million visitors a year. They follow in the footsteps of the late 18thand early 19th-century romantics, most notably the poet Goethe and Britain's William Turner, who was inspired by Heidelberg to paint some of his greatest landscapes. In 1878, Mark Twain began his European travels with a three-month stay in Heidelberg, recounting his observations in A Tramp Abroad (1880). Heidelberg's rich literary history, along with its thriving contemporary scene, saw it named a Unesco City of Literature in 2014. Heidelberg's Altstadt has a red-roofed townscape of remarkable architectural unity. After having been all but destroyed by French troops under Louis XIV (1690s), it was rebuilt during the 18th century. Unlike many German cities, it emerged from WWII almost unscathed. Heidelberg is considered one of the most beautiful cities in Germany. The picturesque ensemble of the castle, the Old Town, and the river Neckar surrounded by hills, which inspired the poets and artists of romanticism, still fascinates millions of visitors from all over the world today. But there's more to Heidelberg than romanticism. Heidelberg is a city of science. It is home to Germany's oldest university, as well as to numerous others, and to a host of internationally renowned research institutes and research-based companies. The International Building Exhibition (IBA) shows the city and the scientific community working together even more closely in the future. Heidelberg is international. About 11.8 million visitors from all over the world come to the city each year. The population, too, is international: an estimated 45,000 of Heidelberg's inhabitants have an immigrant background many of them are scientists and students. Heidelberg is green. The combination of attractive countryside, favorable climate and urban lifestyle makes Heidelberg one of the leading cities in Germany in terms of leisure value. In addition, the city has received multiple awards for its commitment to the environment