In 1925 the wooden structures around the walls were demolished for safety reasons. Following several intermediate restoration attempts, the telescope was restored more completely in the late 1990s. The demesne Situation The demesne runs south and south-east of Birr town centre. The main public entrance is through a courtyard; there is no direct public access to the castle, which faces into the demesne, with an internal gate on a bridge over a dry moat separating the castle's inner surrounds from the broader parkland. The entrance courtyard contains the Science Centre, café, shop and garden entrance, while the family have an ornamental private road gateway, with a large adjoining gate lodge, occupied by a staff member, just to the north. Birr's main river, the River Camcor, enters the demesne near the castle, and continues through a pond to flow into the Little Brosna River, which in turn marks the border between Counties Offaly and Tipperary, and flows on to the Shannon. The demesne is open to the public for a fee, with an annual subscription available for Friends of Birr Castle Demesne. Ireland's Historic Science Centre The castle grounds are also home to Ireland's Historic Science Centre, a museum of Ireland's historic scientists and their contributions to astronomy and botany. The museum lies within a courtyard off William Street. Its displays touch on astronomy, engineering, photography, botany and other topics. Laurence Parsons, 4th Earl of Rosse and his mother, Mary Parsons, Countess of Rosse, were eminent photographers, and her darkroom, which is also on show within the museum, is believed to be the oldest surviving example in the world. Café and shop The Castle Courtyard Café and a small shop are in the same courtyard as the Science Centre. Parklands and gardens The grounds of the castle contain the oldest wrought-iron bridge in Ireland, dating from 1820. There was also an early hydroelectric station by the bridge and castle. The walled gardens in the grounds feature Box Hedges that are over 300 years old. They are also, according to The Guinness Book of Records, the tallest hedge in the world. The Irish entry to the 2014 European Tree of the Year contest was the Birr Castle Grey Poplar (Populus × canescens). In February 2014, while voting was still open, it was blown down in a storm. Membership and sponsorship The demesne's charitable foundation offers quarterly, half-yearly and annual memberships, including unlimited