Zanderij Crailo is the largest wildlife crossing in the world. Construction started in December 2002 and it was officially opened by Queen Beatrix in 2006, costing approximately 15 million euro. With 800 metres in length and 50 metres in width, it connects the Spanderswoud in the west with the Bussumerheide in the east. It is a remarkable engineering feat, as it crosses over a railway, a road, a train maintenance area and a sport park. By connecting the forests of the Gooi area and the Utrechtse Heuvelrug, the crossing created the second largest connected nature area in the Netherlands, strengthening biodiversity in the region.