What is the name of Calatrava's bridge in Seville with a single pylon?

The name of Calatrava’s bridge in Seville with a single pylon is the Alamillo Bridge.

Designed by Spanish architect and engineer Santiago Calatrava, the bridge was built between 1989 and 1992 for Seville’s Expo ’92. It links the city with La Cartuja, the former river island where much of the exposition was held. Its dramatic profile combines a long roadway deck with a steeply inclined tower.

The Alamillo is unusual because its single pylon acts as a counterweight. Unlike a conventional cable-stayed bridge, it has no backstays behind the tower; the massive, concrete-filled steel pylon balances the deck through its own weight. Thirteen pairs of cables support the approximately 200-metre main span.

A common mix-up is the nearby Puente de la Barqueta, another Expo-era Seville bridge associated with the same redevelopment. The Barqueta has a very different arch-and-cable design, while the Alamillo is recognized by its solitary, backward-leaning pylon and harp-like cables. The bridge’s concept was related to Calatrava’s earlier “Running Torso” sculpture.