Some portions of the terrain on the battlefield have been altered from their 1815 appearance. Tourism began the day after the battle, with Captain Mercer noting that on 19 June a carriage drove on the ground from Brussels, the inmates of which, alighting, proceeded to examine the field. In 1820, the Netherlands' King William I ordered the construction of a monument. The Lion's Mound, a giant artificial hill, was constructed here using of earth taken from the ridge at the centre of the British line, effectively removing the southern bank of Wellington's sunken road.