Starting at 1430 Larimer Street, Denver, CO 80202, open the Explorial app and enter the 6-digit game code that you received by text and Viator chat message to begin. The route begins in the historic Larimer Square area, Denver's oldest block and still one of its liveliest. The first riddles take you to the East 2 West Source Point — a landmark marking the geographic heart of Colorado's capital and a starting point for some surprising local trivia. Next, the trail guides you past the Ellie Caulkins Opera House, part of the Denver Performing Arts Complex, whose striking architecture anchors the cultural centre of downtown. From there, the app leads you to the Colorado State Capitol, its gold dome gleaming at exactly one mile above sea level, surrounded by history and political stories stretching back to the 1880s. Around 2 hours of walking, any group size. A fully charged smartphone with mobile data is required.