Besides stone sculpture another art form worth mentioning is woodcarving. No Visitor to the Kathmandu Valley can go without being impressed by the numerous extremely beautiful windows, doors, temple roof-struts and other intricately carved artifacts. As wood is vulnerable to the ravages of time, well-preserved specimens date back only to the fourteenth century. Woodcarving has been an integral part of Nepalese architecture, some of the examples being the old royal palaces of Kathmandu, Patan and Bhaktapur and a number of different Viharas (monasteries) around the Valley.