While in Cologne, you can visit Germany's oldest city hall, with parts dating back to the 11th century. Over time, it has picked up a mix of styles—Gothic tower, Renaissance loggia, some modern touches. The 61-metre tower is covered in carved figures, including some cheeky ones from local history, and the bells chime four times a day. There’s also a mechanical face called the Platzjabbek that sticks its tongue out on the hour. Inside, the Hansasaal is the main historic hall—worth a look if it’s open.

Parco del Valentino is a big public park right in the city centre, next to the river Po. Colourful flower beds, a small stream with wooden bridges and monumental fountains create a peaceful oasis amid the city. During spring and summer, you can chill all day long and well into the evening. The stately Castello del Valentino is the focal point of the park. Within the park, you'll find Borgo Medievale — an open-air museum and reconstructed medieval village and castle. Also, do check the latest exhibition in Promotrice delle Belle Arti and see what's in bloom at the Museo dell'Orto Botanico.

Scattered throughout the Old Town, these twelve churches are among the oldest buildings in Cologne—most of them date back to the 12th and 13th centuries. They’ve all got that heavy Romanesque look, but each one’s a bit different. Great St. Martin stands out with its massive tower right by the river, St. Gereon has got an unusual oval dome, and St. Maria im Kapitol is one of the largest. You don’t need to see all twelve, but stopping in at a couple while you’re exploring the Old Town gives you a good feel for the city’s medieval side.

This world famous oil tanker was torpedoed in the 1940s, and has remained under water ever since. The site is now a popular attraction frequented by divers drawn by the ship's mysterious flair.