UNESCO (the United Nations Educational, Scientific and Cultural Organisation) has added 21 new sites to its World Heritage List, comprising 15 cultural, five natural and one mixed properties. Four sites have also been added to its list of sites in danger.

Among the cultural sites named are the Australian convict sites, 11 in total and mainly around Sydney and in Tasmania, plus Norfolk Island and Fremantle; Jantar Mantar in Delhi, India, a number of architectural astronomy instruments dating from 1724; the 11th century Imperial Citadel of Thang Long-Hanoi in Vietnam; the Tabriz Historical Bazaar Complex in Iran; the Bikini Atoll nuclear test site in the Marshall Islands; and the 17th century canal ring area inside Amsterdam's Singelgracht. The new natural sites include China Danxia; the pitons, cirques and remparts of Reunion Island in the Indian Ocean; the Phoenix Islands protected area in the South Pacific; the Putorana plateau in Russia; and the central highlands of Sri Lanka.

The new mixed site - an existing natural site which has been recognised for its cultural values - is Papahanaumokuakea, a cluster of small, low lying islands and atolls, with their surrounding ocean, around 250km (155 miles) to the northwest of the main Hawaiian archipelago. The sites listed as of being in danger are Bagrati cathedral and Gelati monastery in Georgia; the Madagascan rainforests of Atsinanana; the tombs of the Buganda kings in Uganda; and the Everglades National Park in Florida, US.

A number of existing world heritage sites have been extended, among which are the historic centre and Schloss Eggenberg in Graz, Austria; the Roros mining town and the circumference in Norway; the prehistoric rock-art sites in Portugal's Coa Valley and Siega Verde; and the Ngorongoro conservation area in Tanzania. In a separate development, the UK's nomination for the Down House workplace and home in Bromley, south London, of Charles Darwin to join the list of world heritage sites has been deferred.

The World Heritage Committee said that although the bid was very strong in terms of recognising scientific achievement, further in-depth study and analysis was needed. It has now been referred back to the UK authorities for these issues to be addressed. Culture secretary Jeremy Hunt said the move was disappointing but added: "I'm pleased the committee has recognised the value of the site not only in terms of historical interest, but the celebration of achievements in science, paving the way for including a greater representation of the heritage of science and technology on the World Heritage List."

Image: Jantar Mantar