If you love heights, then you'll love this - a walkway is being built across the roof of the O2 Arena in London!
Thrill-seekers will be able to climb to an observation platform in the centre and check out the amazing views of the capital.
The walkway will be 190m long and will stretch right across the middle of the Dome.
It's hoped it'll be built in time for the 2012 Olympics.
"The lightweight nature of the structure will ensure that the experience is as close to walking on the roof of the tent as possible," said Alistair Wood, who runs the O2.
"Whilst the 60m climb and the fact that the experience is open air will add to the sense of excitement and adrenaline."
The O2 will host the 2012 Olympics basketball and gymnastics events.