You see a lever.
Location
Throughout Tibia, in cities, on the ground, and underground.
Notes
The most common levers seen are those at city gates which supposedly would let the gates down, but are not accessible. Usable levers usually open specific doors, or passages such as teleports or even holes. Some levers are even useless.
Besides the classical lever shown on this page, there are two other types of levers: 
