Each tower is 452 metres tall - higher than the Eiffel Tower in Paris with a small house balanced on top. To reach the very top, a fast lift whizzes you up at around six metres a second. From up there, on a clear day, you can see right across the city and far into the green hills around it.
The most famous part is the Skybridge - a double-decker walkway joining the two towers at the 41st and 42nd floors, 170 metres above the street. The bridge isn't bolted to the towers. It is designed to slide a little as the towers sway in the wind, so nothing snaps. It's like a giant hug that can wiggle.
The towers' shape is taken from a special star pattern. If you look down from above, each tower is shaped like an eight-pointed star, with smaller circles bumping out between the points. The pattern comes from Malaysian art and is meant to feel welcoming.
Building the towers was a huge race. Two different teams - one from Japan and one from South Korea - each built one tower at the same time. They watched each other across the gap and tried to keep up. When they finally connected the Skybridge in the middle, both teams were exactly level, to the millimetre.