Look skywards at the Planetario de Madrid
It’s always free to look around Madrid’s planetarium, which has audio-visual exhibitions looking at all aspects of space and its exploration. There’s a hands-on area for kids, and a domed projection room (which costs extra) that guides visitors through the night sky.
Get lost in Madrid’s barrios
Take a short walk away from Puerta del Sol and you’ll discover some of Madrid’s most colourful barrios (wards). Try multicultural Lavapiés, where shisha bars and Indian restaurants line the graffiti-daubed streets, or hipster-packed Malasaña, known for its nightclubs and vintage clothing shops.
Party on the streets
Street parties and festivals are an important part of Madrid’s social calendar. One of the wildest events is February’s Carnaval, a six-day festival of music, theatre and dance that opens with a fantastical procession of floats and costume-clad performers.
Visit the Royal Palace
Time it right and you can visit the Spanish king’s official residence for free. Unlike his predecessors, Juan Carlos I doesn’t actually live at the Royal Palace, a treasure trove of art and antiquities inspired by the Louvre in Paris, but it is still used for state events. Admission is free for EU residents on Wednesday and Thursday afternoons.
See flamenco for free
Okay, so you’ll need to buy a drink, but the late-night restaurant Clan gives you the chance to see authentic flamenco performances for free. The music starts sometime after midnight on Fridays and Saturdays, and dancing carries on until 3am.