Introduction to Heidelberg: Heidelberg is located between Stuttgart and Frankfurt and is a city in the German state of Baden-Württemberg. Heidelberg is the epitome of romantic Germany. The winding and quiet alleys connect old castles and rivers, and are full of poetry and painting. At the same time, it is also a vibrant mix of tradition and modernity. In the past it was a center of science and art, and today Heidelberg continues the tradition with many research centers built in and near the city.