Parc Diagonal Mar

Forget the mossy fountains and the crumbling stone of the Gothic Quarter for a second. If you want to see where Barcelona is actually going—or at least where it thought it was going at the turn of the millennium—you head to Sant Martí. Here, on the site of a former smelting plant, sits Parc Diagonal Mar. It is a sprawling, 34-acre architectural statement that feels less like a city park and more like a set piece from a high-budget sci-fi flick where the robots eventually win.

Designed by the late, legendary Enric Miralles and his partner Benedetta Tagliabue, this place is a masterclass in 'what the hell is that?' It’s built around the concept of a 'Tree of Life,' but don’t expect anything leafy and literal. Instead, you get massive, undulating steel tubes that snake through the air like frozen lightning, occasionally dipping down to become benches or support structures for hanging plants. It’s industrial, it’s aggressive, and it’s strangely beautiful in its refusal to be pretty.

The first thing you’ll notice, besides the sheer scale of the metalwork, is the sound. Not the sound of nature, but the sound of pure, unadulterated joy and the occasional terrified yelp. That’s coming from the slides. These aren’t the plastic, sun-faded chutes you find at a suburban McDonald’s. These are massive, wide, stainless steel toboggans built into the side of a man-made hill. They are fast, they are loud, and they are the primary reason people trek out here. You’ll see kids, sure, but you’ll also see grown men in business suits and grandmothers in sensible shoes taking the plunge. It’s a visceral reminder that gravity is the great equalizer.

Then there’s the water. The park is anchored by a massive lake that isn't just there for the ducks. It’s part of a sophisticated, sustainable system that uses groundwater to keep the place alive. The lake is surrounded by 'trencadís'—those broken tile mosaics that Gaudí made famous—but here they’re used on giant, bulbous planters that look like they’re melting into the pavement. It’s a nod to the past while firmly flipping the bird to traditionalism.

Is it perfect? No. The salt air from the nearby Mediterranean is a cruel mistress, and you can see the rust starting to chew at the edges of Miralles’ vision. Some parts feel a bit desolate when the sun goes down, and the proximity to the massive Diagonal Mar shopping mall means you’re never far from the hum of consumerism. But that’s the truth of modern Barcelona. It’s a city trying to reconcile its industrial bones with its high-design future.

You come here when you’re tired of the crowds at Park Güell. You come here when you want to see how a city breathes when it’s not trying to sell you a souvenir t-shirt. It’s a place for dogs to run, for lovers to hide in the shadows of giant steel pipes, and for anyone who appreciates the fact that sometimes, the best thing a city can give you is a giant metal slide and a bit of weirdness. It’s one of the best things to do in Sant Martí if you want to escape the tourist loop and see a neighborhood that’s still figuring itself out. Just watch your speed on those slides; the metal doesn't care about your dignity.