There's nothing quite like Barcelona. Especially if you consider the architecture. The city lays claim to its very own form of Art Nouveau, known as Modernisme.
The Sagrada Familia Basilica is perhaps the best example of this beautiful and interesting brand of architecture, with its bold color, beautiful tile-work and swirling lines. At the same time, many find the work at the Picasso Museum and the cathedrals of the Gothic Quarter equally inspiring.