Located near the Neckar River in Southwest Germany, Heidelberg is one of the most visited cities with the oldest university in the country. There is a unique blend of old and new in the city, and anyone interested in architecture will find many different types of buildings to appreciate. The gothic Heiliggeistkirch church is one of the best-known architectural wonders, overlooking the town square of Altstadt. The Heidelburg Castle, built in 1751, sits on Konigstuhl Hill and houses the biggest wine barrel in the world (the Heidelburg “Tun”). In addition to active architectural, cultural, business, scientific and technical communities, Heidelberg is also ahead on the environmental front. In the late 1990s the city started setting an example for conscious sustainability in the country, winning the top German prize for nature preservation and protection of the environment in 1996 and the European Sustainable City Award in 1997. As a growing biotech hub, the city is home to various companies in the Rhein-Neckar Bioregion. Heidelberg has an active art scene in both physical and written forms, and locals and visitors alike can enjoy a plethora of options for food and drink. There is also a strong music and cultural scene, with ten museums, five theaters and a diverse range of galleries that are open year-round.