Barcelona’s very own cucumber-shaped tower, Jean Nouvel’s luminous Torre Agbar (which houses the city water company’s headquarters) is the most daring addition to Barcelona’s skyline since the first towers of La Sagrada Família went up. Completed in 2005, it shimmers at night in shades of midnight blue and lipstick red. Unfortunately, you can only enter the foyer on the ground floor, frequently used to host temporary exhibitions on water-related topics.