Hundreds of children will help build the tallest record tower in history this week which will eventually stand 30m tall and weigh 1.5 tonnes.
The tower, behind the city hall in Vienna, will beat the previous world record set in Britain of 29.26m.
A crane has been used to put Lego pieces on the highest point of the tower. The attraction has become a big hit for tourists visiting the Austrian capital.
The tower withstood high wind speeds of 60 Km/h this weekend to prove it is a formidable structure.
Hundreds of children will help put the Lego blocks together which can then be put on the tower by crane. As soon as the world record is recorded the tower will be dismantled.
Meanwhile, in Germany hobby workers are constructing what they hope will be the world's largest Lego bridge.