“For a place to become a tourists’ favorite, it must have three things: a castle or fortress, a river, and an old bridge,” my friend LW told me when she was visiting earlier this month.

I’m hesitant to generalize this to all popular destinations in the world, but that might explain why Heidelberg attracts more than 3.5 million visitors every year.

With 14 districts in 6 sectors, Heidelberg is the fifth-largest city in Baden-Württemberg; but a lot of visitors still consider it a small town – that’s because most of them choose to stay in the old town (Altstadt), where all the attractions stand.

Beginning from Bismarckplatz, follow the mile-long main street (Hauptstraße) – also the longest shopping street in Germany – which runs through the entire historic city, passing by hundreds of shops, narrow alleys and famous squares, including the University Square (Universitätplatz or simply Uni-Platz), Corn Market (Kornmarkt or Kornplatz) with the statue of Virgin Mary, and Karlsplatz, where you get a clear view of the Heidelberg castle from below. The street ends at Karlstor, a centuries-old gate that marks the east end of the old town.

Parallel to the Hauptstraße is the Neckar river. I remember crossing the river through the old bridge (Alte Brücke) for the first time and was absolutely in awe of the scenery. In the foreground the Neckar flows steadily below the red-brick bridge, and in the background the magnificent castle rises above the beautiful old town – a postcard-perfect picture right in front of my eyes. It gets even better when you hikes up to the Philosopher’s Walk (Philosophenweg) for the mesmerizing panoramic views of the Altstadt (which LW described as “as lovely as those of Prague’s”).

But Heidelberg isn’t just a tourist town. It’s home to Germany’s oldest university, the Ruprecht-Karls-Universität Heidelberg, and over 30,000 students out of a total population of around 150,000. In other words, every one in five people here is studying at the university. During the academic year, streets in the Altstadt and Neuenheim (another district) are filled not only with travelers but also students on their bikes rushing between classes as university buildings are spread across the two areas of the city.

I’m really lucky to have a flat in the old city center so I don’t even need a bike to get around. It’s on a long street called Plöck, which is parallel to the Hauptstraße, and my department is also on the same street. The convenient location allows me to enjoy daily sunset walks around the beautiful town and along the river after class, and meeting people was never easier. More on my flat next time!