Starting at Brunswick Street, Liverpool L3 4AE, UK, open the Explorial app and enter the 6-digit game code that you received by text and Viator chat message. The riddles take you from the waterfront through one of Britain's most celebrated city centres. Your first stop is the Beatles Statue on the Pier Head — four bronze figures heading toward the water, capturing the moment before everything changed, and marking the spot where Liverpool's most famous export still draws visitors from every corner of the world. Next, the app takes you to the Cavern Club on Mathew Street, the subterranean venue where the Beatles played nearly 300 times before they were famous, and where the city's musical legend was first heard above ground. The route then leads to St George's Hall, one of the finest neoclassical buildings in the world, whose columns and concert hall stand at the top of Lime Street as evidence of the wealth and ambition that made Liverpool a Victorian powerhouse. Around 2 hours on foot. The waterfront is flat; the city centre involves gentle hills. Both are worth every step.