1. Dusseldorf Old Town, or Altstadt, is known as the \"longest bar in the world\" due to the high concentration of bars, pubs, and breweries in the area. The historic district dates back to the Middle Ages and features charming cobblestone streets, traditional architecture, and the iconic Rheinuferpromenade along the Rhine River. Altstadt is also home to St. Lambertus Church, Schlossturm (Castle Tower), and the Kunstsammlung Nordrhein-Westfalen modern art museum.

2. The Dusseldorf Old Town is open all year round and is free to enter. However, individual businesses within the district may have varying operating hours. It is recommended to check with specific establishments for their opening times. For general information, you can contact the Düsseldorf Tourism Visitor Center at +49 211 172020.

3. Public transportation is the best way to reach Dusseldorf Old Town. The nearest metro stations are Heinrich-Heine-Allee, Benrath, and D-Grabbeplatz, all of which are accessible by various tram and bus lines. There is no entry fee to visit Altstadt, but be sure to bring some cash for food, drinks, and shopping in the area.