Barcelona is one of the few great European cities by the sea. While Madrid withers in the summer sun, Barcelona chills out on its beach. Its main thoroughfare, Las Ramblas, runs all the way from the quayside through the heart of the city and it is here that you should start your tour of one of Europe's most exciting cities. Barcelona is busy all day, but really comes into its own at night when Spanish and foreign visitors come out to parade up and down the streets and relax in the hundreds of bars and restaurants on offer. The Catalan capital is widely known as a party city and you will inevitably get carried along with the spirit. But don't stay out too late - there is plenty to see by day.