The dragon boundary marks are cast iron statues of dragons on metal or stone plinths that mark the boundaries of the City of London. The dragons are painted silver, with details of their wings and tongue picked out in red. The dragon stands on one rear leg, the other lifted against a shield, with the right foreleg raised and the left foreleg holding a shield which bears the City of London's coat of arms, painted in red and white. The design is based on two large dragon sculptures, 2.10 m (7 feet) high, which were mounted above the entrance to the Coal Exchange on Lower Thames Street in 1849.