MADRID, SPAIN. A two-minute walk away from the Campo de las Naciones metro station, just a half-hour metro ride from the center of Madrid,  Juan Carlos I park is full of gardens, canals and bike paths with views of the Madrid skyline and the Sierra de Guadarrama Mountain range.

One of its main attractions is its bike-rental system, which allows anyone to hire a bike for up to an hour – completely free of charge. There are three rental points in the park, and each is marked by a huge red sphere.

Bikes are available to rent from ten a.m. to one p.m. and from four thirty p.m. until seven thirty p.m. Monday to Friday, and from nine thirty am until seven thirty pm on Saturday, Sunday and national holidays. You must provide a form of identification at the time of the rental. Helmets are also provided.