May 21-22, Sant Feliu de Guíxols. Oxfam Trailwalker

The annual race Oxfam Trailwalker, taking place in the Costa Brava every March-April, is a popular endurance event whose premise is simple: the participants need to cover the 100 km distance between Olot and Sant Feliu de Guíxols in 32 hours.

You may run, walk or crawl, take breaks for food and rest whenever you want, break for the night or keep going till the end — each team (four people required) has its own strategy and tactics.

Find out more about the race, its history, and the organizing charity Oxfam here.