The U.N. agency mandated to conserve the world's culture added five sites to its World Heritage List on Sunday, including the Imperial Citadel of Thang Long-Hanoi in Vietnam.

That citadel, built in the 11th century by the Ly Viet Dynasty, became the 900th site listed as a World Heritage Property.  With the other four sites added, the total increased to 904.

The 21-nation UNESCO (United Nations Educational, Scientific and Cultural Organization) World Heritage Committee chose the new sites at a 10-day meeting in Brazil, updating its list of top spots for historical interest or natural beauty.

So far during the meeting, the Paris-based UNESCO has added 17 new sites to the list, including Bikini Atoll in the Marshall Islands, home to nuclear bomb testing in the 1940s and 1950s.  UNESCO also added an Australian penal colony set up by the British to house deported convicts in the 18th and 19th centuries.

In the Middle East, Iran won a listing for the historic bazaar complex in the northern city of Tabriz and a Sufi mystic shrine complex in Ardabil, as did Saudi Arabia for its former dynastic capital, the 15th century Turaif District.

The European sites listed include the medieval cathedral city of Albi in southwestern France and Amsterdam's historic network of urban canals.  In Romania, a site encompassing seven churches built in the 15th and 16th centuries that had previously gained World Heritage status was expanded to include the Church of the Sucevita Monastery.

Portugal's ancient rock art in the Coa Valley also was expanded to include 645 prehistoric engravings on a cliff in Siega Verde, in Spain's Castilla y Leon region.

On Friday, UNESCO announced that it will wait until next year to settle a dispute over a Hindu temple site resting on disputed land between Thailand and Cambodia.
That announcement came a day after Thailand threatened to withdraw support from the United Nations agency if it backed a Cambodian management plan for the Preah Vihear temple.  Thai-Cambodian border tensions flared in July of 2008 over the 900-year-old Khmer temple after UNESCO declared it a World Heritage site under Cambodian control.

The UNESCO committee also voted to remove Ecuador's Galapagos Islands from its list of endangered sites.

Some information for this report provided by AP and AFP.