Being on holiday is a great way of discovering new cities as well as places you have been to before. The days of carrying a guidebook are over, thanks to the many alternative offers available, like guided walking tours or apps. Secret City Trails is a curated marketplace for city discovery games created by locals. During a game, players solve a trail of riddles via an online web app and explore a new city in a completely different way. You can use the web app in 40 European cities and learn a lot about their culture, history and art. We talked to Co-founder Wendy van Leeuwen about the web app and its benefits, the development of a city game and how to become a developer.