Heidelberg
Heidelberg has three self-guided routes, and all of them begin when you do: buy a ticket, open the World City Trail app, and set off.
The Heidelberg Scavenger Hunt and Self-Guided Tour (€11) places a puzzle at each landmark along the way. The Heidelberg Escape Game (€11) plays the city as an outdoor escape room. The Heidelberg Self-Guided Walking Audio Tour (€9) is narration without the puzzles. Voice narration is optional on all three.
The routes climb to the majestic Heidelberg Castle overlooking the Neckar River. Because nothing is scheduled, you can start early, start late, or break halfway and come back — the ticket stays valid and the app picks up where you left off.
