Starting at Rua Roquete Pinto in Urca, Rio de Janeiro, Brazil, you'll open the Explorial app, enter the 6-digit game code that you received by text and Viator chat message, and set off into one of Rio's most atmospheric neighbourhoods. No guide, no fixed start time. Your first stop is the Mureta da Urca, the low seawall that has been a gathering spot for Rio locals for generations. With Sugarloaf rising directly behind you and the bay stretching ahead, the riddles pair Rio's best views with the stories of the neighbourhood beneath the mountain. The route then leads to the Museu de Ciências da Terra, housed inside a striking early 20th-century building in the heart of Urca. Its collection of rocks, minerals, and fossils tells the geological story of Brazil. The hunt finishes at Praia Vermelha, the small sheltered beach at the very foot of Sugarloaf. Named for its distinctive reddish sand, it's one of the few truly peaceful beaches in Rio de Janeiro. Allow around 2 hours for the full route. Urca is a neighbourhood that Rio keeps to itself — and this tour is your way in.