TEHERAN • Once, a musician mistook the glossy surface for a platform and stepped right inside.
He ended up covered in oil.
Now, 40 years after Noriyuki Haraguchi's "oil pool" sculpture became the centrepiece of Teheran's first modern art museum, the Japanese artist returned for its restoration over the weekend and found a place "frozen in time".
When the Museum of Contemporary Art opened in central Teheran in 1977, just two years before the Islamic revolution, the country's cultural scene was flush with royal patronage.
Queen Farah was determined to make Iran a global centre of the arts and gathered masterpieces by the likes of Pablo Picasso, Joan Miro and Andy Warhol - a collection now valued in the hundreds of millions of dollars.
She commissioned Haraguchi for the focal point at the foot of the museum's spiral stairway: a large rectangle of thick waste oil that looks like brightly polished black stone.
When her husband, the late Shah Mohammad Reza Pahlavi, saw it for the first time, he did not believe it was liquid and ended up with his hand covered in oil.
"It was very interesting for me to see my work again here, 40 years later, still standing intact. I was really surprised," Haraguchi, 71, said.
"I have made about 20 of these oil pools around the world and there is only one place where it has remained intact like this, and that is here," he added, noting that others are now in museum archives.
"It feels like time has frozen in this museum since I created this, and it is only me who has aged."
Most of the Western artworks in the museum were declared unIslamic and hidden away in the basement for decades after the revolution - though some have been put back on display occasionally in recent years.
Restoring the oil pool meant fishing out hundreds of items dropped into it over the years, mostly coins.
It also needed an additional 800 litres of oil, its depth having been reduced by around 2.5cm.
"For 40 years, the staff and visitors have seen this artwork here every day. It has become woven into the museum's flesh and blood," said director Ali Mohammad Zare.
The pool measures 6.4m by 4.2m and is 18cm deep, containing more than 4,500 litres of waste oil.
Though it is known as the "oil pool" in the Farsi language, its official name is Matter And Mind.
Asked about the meaning of his work, Haraguchi said it was simply a way of connecting people.
"Art should be free and, through art, people can communicate, which is the most important thing and the reason why I'm sitting here now," he said, adding he hoped to one day create new works in Iran.