Birr Castle Demesne is without doubt the star attraction of Birr. The immense grounds (the castle is closed to the public) are home to a lake and two rivers and over 1,000 species of plants (some of which from the Himalayas, China and South America) and the highest yew hedges in the world (12m/40ft). The giant telescope (1840) and a hanging bridge add variety to this walk and bear witness to the Pearson family's passion for technical innovations.