Santiago Calatrava's white-concrete fantasia is what most people picture when they think of modern Valencia. Stretched along nearly two kilometres of the former Turia riverbed, the complex includes an opera house (the Palau de les Arts Reina Sofía), a planetarium and IMAX (L'Hemisfèric), a science museum (Museu de les Ciències), an oceanarium (L'Oceanogràfic), a Felix-Candela-shaped greenhouse (L'Umbracle), and a covered exhibition space (L'Àgora).
The complex looks best at twilight, when the white shells reflect in the long blue pools that wrap around them. You can walk the whole site for free; pay for entry to the individual buildings. L'Oceanogràfic is the most family-friendly, the Science Museum is the most hands-on, and the opera house is worth seeing from outside whether or not you catch a show.