No wonder Freddie Mercury sang the praises of Barcelona. Continually topping the city break charts, this buzzing metropolis has the power to bowl any visitor over. And if you want to tick through its main sights in a day, then this guided tour which includes Antonia Gaudi's bonkers buildings, is for you. You'll see two of the Spanish architect's best-known creations - the soaring Sagrada Familia, a cathedral resembling a wave-worn sandcastle, and Park Guell, peppered with his fairytale sculptures. You'll also have time to stroll the pedestrianised street of Las Ramblas, perhaps watching its street entertainers, hunting for souvenirs or grabbing a tapas lunch. Last but not least is a visit to Montjuic mountain, home to the magnificent 1992 Olympic Stadium and more bird's-eye views of the city. One word, though - there's quite a lot of walking involved, so wear comfy shoes!