CANBERRA A Japanese silver mine and a Parthian fortress in Turkmenistan, both dating back to the 1600s, were among four sites added to the United Nations World Heritage list on Thursday.

The UN's cultural organisation Unesco also inducted an ancient fort in India and the Sydney Opera House to the World Heritage list at a meeting in Christchurch, New Zealand.

Unesco said it had included the Iwami Ginzan Silver Mine, southwest of Japan's Honshu Island, which contains the remains of large scale mining, smelting and refining sites worked between the 16th and 20th centuries, because of its role in boosting Japan's economy.

"The high quality of the silver resulting from the use of advanced techniques, and the quality of silver mined, contributed substantially to the overall economic development of Japan and Southeast Asia in the 16th and 17th centuries, and prompted the mass production of silver and gold in Japan," Unesco said.

In Turkmenistan, Unesco listed the Parthian Fortresses of Nisa, which contain remnants of two cities from the Parthian empire from the mid 3rd century BC to the 3rd century AD.

"Archaeological excavations in two parts of the site have revealed richly decorated architecture, illustrative of domestic, state and religious functions," Unesco said.

In India, Unesco listed the Red Fort Complex, built for Mughal Emperor Shahjahan, who ruled between 1628 and 1658.

The palace, which gets its name from massive enclosing red sandstone walls, was designed to imitate paradise, as it was described in the Koran.

"The Red Fort is considered to represent the zenith of Mughal creativity which, under the Emperor Shahjahan, was brought to a new level of refinement," Unesco said.In Australia, Unesco said the Opera House, designed by Danish architect Joern Utzon, was a great artistic and architectural monument of the 20th century.

Utzon was a largely unknown architect when his design for the Opera House was selected in 1957.

                              Reuters