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.
The Shard's title of the tallest in Europe could be short-lived though.
The Mercury City Tower in Russia is set to be taller when it's completed by the end of the year!
If you want to check out what's set to be an amazing view from near the top of the Shard, they're selling tickets and it'll be open to the public from February.
But they're not cheap - £24.95 for adults and £18.95 for children!