Agong (Supreme King), the head of state of Malaysia. The Yang di-Pertuan Agong has a palace, referred to as an istana. Each of the other sultans has their own istana, located in their state. Throughout the country they are sometimes called Istana Hinggap. The Yang di-Pertuan Agong's official residences are the Istana Negara, Jalan Duta, the Royal Museum, and Istana Melawati, a palace and retreat, located in Putrajaya. Some of the other official palaces are the Istana Besar, Istana Anak Bukit, Istana Pekan, Istana Maziah, Istana Alam Shah, Istana Balai Besar, Istana Besar Seri Menanti, Istana Iskandariah and Istana Arau. Several appointed governors, or Yang di-Pertua Negeri, are also assigned to have their official seat and residence such as The Astana, Istana Negeri Sabah and Seri Mutiara. Nepal Singha Durbar (literally, Lion Palace) in Kathmandu is the official seat of government of Nepal. Narayanhiti Palace Museum was a residence and principal workplace of the reigning Monarch of the Kingdom of Nepal. It was built by king Mahendra in 1961 under the design of Californian architect Benjamin Polk. After the 2006 revolution, this royal palace is turned into a public museum. Older palaces include the Durbar Squares, which are enlisted as UNESCO World Heritage Sites. They are located in Kathmandu Valley in districts of Kathmandu, Bhaktapur and Lalitpur. In Kathmandu is Kathmandu Durbar Square, Bhaktapur Durbar Square in Bhaktapur, Patan Durbar Square in Lalitpur. Kathmandu Durbar Square (Basantapur Darbar Kshetra) in front of the old royal palace of the former Kathmandu Kingdom is one of three Durbar (royal palace) Squares in the Kathmandu Valley in Nepal, all of which are UNESCO World Heritage Sites. Several buildings in the Square collapsed due to a major earthquake on 25 April 2015. Durbar Square was surrounded with spectacular architecture and vividly showcases the skills of the Newar artists and craftsmen over several centuries. The Royal Palace was originally at Dattaraya square and was later moved to Durbar square. The Kathmandu Durbar Square held the palaces of the Malla and Shah kings who ruled over the city. Along with these palaces, the square surrounds quadrangles, revealing courtyards and temples. It is known as Hanuman Dhoka Durbar Square, a name derived from a statue of Hanuman, the monkey devotee of Lord Ram, at the entrance of the palace. Bhaktapur Durbar Square is the plaza in front of the royal palace of the old Bhaktapur Kingdom. It