In this hair-raising selfie by Mustang Wanted, we see the grid layout of Barcelona’s Eixample district, as seen from the top of the world-famous Sagrada Familia church designed by Antoni Gaudi.

Mustang Wanted is well known online for his (often illegal) rooftopping escapades. As for the unmistakable grid pattern seen in the background, Wikipedia adds:

The Eixample is characterized by long straight streets, a strict grid pattern crossed by wide avenues, and square blocks with chamfered corners (named illes in Catalan, manzanas in Spanish). This was a visionary, pioneering design by Ildefons Cerdà, who considered traffic and transport along with sunlight and ventilation in coming up with his characteristic octagonal blocks, where the streets broaden at every intersection making for greater visibility, better ventilation and (today) some short-stay parking space. [source]