Relics of Gautam Buddha will be placed above a keystone of what is claimed to be the world's largest stone-built dome at Gorai Island in north Mumbai.

The dome is part of a pagoda being built by the Global Vipassana Foundation at a cost of Rs 80 crore.

The construction of the entire complex -- consisting of the main pagoda which will be 96.12 metres high and four smaller ones with a height of 23 metres each -- will be complete in a year, the foundation said.

To put it in perspective, the main pagoda will be as high as a 30-storied skyscraper.

The centrepiece of this complex, a 100-foot central dome built of stone, is complete. The foundation is going to place relics of Gautam Buddha in a small chamber above the top keystone of the dome in a ceremony on October 29. The Mahabodhi Society donated the relics.

The foundation has requested Prime Minister Manmohan Singh [Images] to do the honours, but it is yet to be confirmed whether he will attend the ceremony.

S N Goenka, who made the ancient Vipassana -- a technique of meditation traced back to the Buddha himself � popular across the world, conceived the pagoda with the gigantic stone dome.

The pagoda will be a huge Vipassana centre that can accommodate around 8,000 people at a time. The land on which it stands was donated by media baron Subhash Chandra Goyal, himself a Vipassana practitioner.

According to the foundation, the pagoda's central dome is the biggest of its kind -- more than twice the size of the Gol Ghumat of Bijapur. But more than its dimensions, the technique used in its construction is newsworthy -- not a single pillar supports the dome.

According to Madan Mutha, a civil engineer and member of the Global Vipassana Foundation, the structure is built of interlocking stones. "Due to interlocking, the entire structure supports itself and no pillars are needed," he explained.

Even cement was used sparingly, Mutha said. The stone used is pinkish Jodhpur stone, brought from Rajasthan.

Each stone weighs around 500 kg. The keystone, which went into the highest point at the centre of the dome, weighed four tonnes.

The area covered by the dome is 6,272 sq metres. The structure will have a water harvesting facility that is expected to collect 1,725,000 litres of water every monsoon, the foundation said.