arch sweeps high over a narrow footbridge, and a steep staircase spirals up vertically, onto a circular cement platform perched on a curvaceous pillar.

Inside the vast grey grounds of the Tripoli International Fair in northern Lebanon, a palm tree throws its dark silhouette onto a giant concrete dome.

This month, a rare exhibition is being held at the site designed by legendary Brazilian architect Oscar Niemeyer in a desperate call to save it from ruin.

Close to the seafront in Lebanon's Tripoli, giant curves of concrete stand testimony to dreams before the civil war, etchings of an exhibition park never finished but already cracking.

"It's a futurist paradigm that is unique in Lebanon and the region," said Lebanese architect Wassim Naghi.

s largest works outside Brazil (photo by: ANWAR AMRO/AFP)

"In its modernity, in its reliance on curves, it sums up the progress of architecture over a hundred years," he said.

And with buildings dotted over an area the size of 70 rugby pitches, it's among "Niemeyer's largest works outside Brazil", he said.

The Brazilian architect designed landmarks around the globe during a decades-long career that started in the 1930s and ended in the 21st century.

When he died six years ago aged 104, he left behind hundreds of buildings, in Brazil as well as in the United States, France, Malaysia, Algeria and Cuba.

Space programme

But today his work in Lebanon is in urgent need of restoration.

"These buildings of reinforced concrete need to be restored rapidly. There are buildings being eaten away at, blocks falling down, and many cracks," Naghi warned.

"We fear there will be unpleasant surprises, especially during the rainy season," he said.

A visitor takes a picture of the stone pyramid at the grounds of the Tripoli International Fair (photo by: ANWAR AMRO/AFP)

Until October 23, a show titled "Cycles of Collapsing Progress" seeks to celebrate the era that gave rise to the fairground, but also sound the alarm.

In the halls under the perched platform, visitors can admire a seabed of snaking rebar, or even an elongated white space rocket hanging from the cieling.

The show "documents a golden age in Lebanon's modern history -- the architectural, scientific and cultural dreams of the time", said curator Karina al-Helu.

During the 1960s, the tiny Mediterranean country had its own space programme, successfully launching a small unmanned rocket into space.

When

Niemeyer was first asked to design the outdoor space in 1962, there were plans for the rooms under the circular platform to house a space museum.

But dreams of outer-space exploration, and any museum to commemorate it, were indefinitely put on hold with the outbreak of the 1975-1990 civil war.

The exhibition aims to remind Lebanese visitors of this chapter of the country's recent past, Helu said, but also shine a light on a landmark about to collapse.

UNESCO list?

In a country whose history goes back millennia to the Phoenician period, she urged the authorities to give equal attention to modern architecture.

"It's great to restore buildings that show Lebanon's ancient history, but we should also care about the landmarks of this country's modern history," she said.

Lebanon is seeking to have the Fair listed as a UNESCO World Heritage site (photo by: ANWAR AMRO/AFP)

Architect Naghi said he was not optimistic about any immediate intervention by the government.

"The current atmosphere of crisis in the country doesn't bode well," he said, referring to a months-long deadlock over forming a cabinet.

Any renovation should involve in-depth studies and specialised companies, he said, "and that would require a lot of money, as well as a government decision".

Instead, Naghi and others hope that the site can be added to UNESCO's World Heritage List.

Brazil's capital Brasilia and an outdoor centre in the south of the country, both of which were designed by Niemeyer, are already featured on it.

Sahar Baassiri, Lebanon's delegate to UNESCO, said efforts were now being made towards adding the concrete park to the list's contemporary architecture section.

Akram Oueida, president of the fairground, said Lebanese officials have made promises of assistance, but none have yet materialised.

Getting the concrete park listed by UNESCO may help, Oueida said: "That could open the door to funding from donors."