Not many people are aware whilst driving into Enniskerry on the R117 that they passing over the Knocksink Bridge. When it was built in 1859 it was Ireland’s highest bridge spanning over a deep glaciated ravine over the Glencullen River. This was an amazing feat of early Victorian engineering. During WWII holes were drilled in the bridge in order to blast it with dynamite in case of a Nazi invasion. The Glencullen River, a tributary of the Dargle flows under this bridge along a deep glaciated ravine called Knocksink Woods. This site has one of the most diverse and important woodland invertebrate faunas in Ireland and is classified as a Special Area of Conservation. The wood is has mixed broadleaf, dominated by Sessile Oak, Holly and Hazel and other species including Ash, Beech, Sycamore and the occasional conifer.The wildlife includes Red Squirrel, Badger, Rabbit and Deer as well as large populations of Robin, Blackbird, Song Thrush, Wren, Chaffinch and Crow. A Buzzard has been noted in the area and Dippers are occasionally seen in the river. There is an educational centre within the site that offers training courses in environmental conservation and countryside management and has facilities for primary school teachers to bring classes to the wood for a visit.