The valuable nature reserve “Verdronken Toren” (Drowned Tower) or “Grote Zenne” (Big Zenne) in Lembeek is a cut off meander of the Zenne river. It offers a wide range of habitats with a varied fauna and flora.
In 1854 the Malakoff Tower was built by Paul Claes, the then Mayor of Lembeek. Later, material from the widening of the Brussels-Charleroi Canal was used to increase the size of the meadow in which the Tower stands.
The old Icehouse is now an ideal place for bats to overwinter. In 2007 it was awarded the environmental prize by the province of Vlaams-Brabant. It was fitted out by volunteers from the Bat Working Group West-Brabant with the support of the city of Halle and the Agency for Nature and Forest, the owner and administrator of the area.
The Tower has never experienced a single real siege, apart from being a stage for the battle of Malakoff which took place during a flamboyant garden party. The Tower owes its current name to this specific garden party. The siege of Malakoff was a notable battle from the Crimean War (1853-56). The battle of Malakoff (on the Crimean peninsula) was fought between the French and the Russian armies on 7 September 1855 as part of the siege of Sevastopol. The French eventually won.
The tower was built from local stone, sporting broken battlements and stone blocks at its base. The concrete spiral staircase is from a much more recent date. The grounds in which the tower stands was part of the castle park of Lembeek, located on the opposite bank of the Canal and the river Zenne. When the castle was sold to the Brothers of the Christian schools, they abandoned this park and allowed nature to take over again.
Hay making takes place one a year on the lawns. The part of the forest along the Dr. Spitaelslaan is thinned every eight years. The last thinning was in 2015. The rest of the area is left alone as much as possible. There are plans to remove the sludge (24,000 m³) to clean the meanders in 2014 and to restore one of the ponds as a fishing pond. There are plans to construct a bird watching wall in the natural area.