After a decade closed, this supremely ugly Madrid landmark just in front of the Museo de América reopened in April 2015. It looks out over the northern corner of the Parque del Oeste and has sweeping views of western Madrid. It was built in 1992 to commemorate the 500th anniversary of the discovery of America and to celebrate Madrid’s role that year as the European Capital of Culture. Sunset is the perfect time to visit.

You're allowed to enter every half-hour from 9.30am to 1.30pm, whereafter it's less restrictive.