Tallest building in Europe opens
5 July 2012 Last updated at 17:12 BST
Europe's tallest building, the Shard in London, will be officially opened with a massive display of lights and music.
It's 310 metres tall, and cost one-and-a-half billion pounds to build.
It'll have offices, restaurants and a hotel, as well as some seriously expensive flats - each costing about fifty million pounds.
There's still work to be done inside. The whole interior will be finished by next year.