[ Oct.2015 ] When you walk along the Motlawa River in Gdansk in Poland, you will not miss this black wooden building.
This is the crane.
I could not understand this at first, but there are big wheels inside this building, whose diameter is 5 metres.
Apparently, four people used to be in the wheels and walk to turn it, just like hamsters, to hoist loads of up to 2 tons from the cargo boats anchored in the river.
It was built in the middle of the 15th century and it was the largest crane in the world then.