Lifts are wooden devices that Ezio can use to be lifted to a higher location very quickly. To use these devices approach the front of the lift and press Forward + RT (Xbox 360) or Forward + R2 (PS3). Ezio will be lifted up to the next area above.
Lifts are only able to be used once at each location. If you approach a lift and there is no string attached to the device then the lift has already been used and can not be used again.