There is a mall beneath it where one can shop or even just have lunch before or after viewing the structure.
Apart from just viewing it from afar, there are some activities within the structure like riding up until reaching the skybridge. It is in between the two towers on 41st and 42nd floors, which is the highest 2-story bridge in the world.It is not directly bolted to the main structure, but is instead designed to slide in and out of the towers to prevent it from breaking during high winds. The bridge is 170 m (558 ft) above the ground and 58 m (190 ft) long, weighing 750 tons.The same floor is also known as the podium, since visitors desiring to go to higher levels have to change elevators here. The skybridge is open to all visitors, but free passes (limited to 1700 people per day) must be obtained on a first-come, first-served basis. Visitors are only allowed on the 41st floor as the 42nd floor can only be used by the tenants of the building.
But still, I think the challenge here for any shutterbug or traveler is take that ultracool and amazing Petronas Towers shot. Here are some of the best Petronas Towers shot I found from the net (wikipedia)!!! Amazing!!!
and my shots of course using Holga my lomocam =)