The Petronas Towers are some of the highest buildings in the world. They are  452 meters tall. Following the most recent details: the Bamboo Shoot in Taiwan is at this moment the highest building in the world.  
Also the KL-Tower in Kuala Lumpur is just a little bit higher than the Petronas Towers, but that's a little joke: the KL-Tower (telecommunication Tower) has been built on a hill and that's why it is a bit higher. 

The two towers are connected by a sky bridge. When you want to visit the towers, then the sky bridge is the highest point you can get. At this level is also a restaurant located.
If you would like to visit the towers, I would like to advise you to collect your free tickets before ten o'clock. Otherwise it would become late afternoon  to go up the tower. If you collect your free ticket early in the morning, than there is on the ticket the exact time, when you should be at the elevator to go up. 

Do you come at ten o'clock, the exact time should probably 13.00 to go up to the sky bridge.