Viktor Melnikov, 91, opens the gate in front of his father's unique house-studio on a secluded lane in central Moscow and beckons me inside. "See for yourself, the work of a genius, a burning star, almost destroyed," he says sadly as he leads his visitors to the door.
The fluid, magical building was constructed in 1927 by his father, the celebrated constructivist architect Konstantin Melnikov, in the form of two interlocking cylinders studded with rhomboid windows. The Melnikov House is one of the last survivors from a brief period of creative brilliance that flourished in Russia between the two world wars, before it was crushed by Josef Stalin.
And now, even the future of this enduring icon is under threat. Moscow is becoming choked with shopping malls and skyscrapers that overshadow whole neighbourhoods, and preservationists warn that the country's unique legacy of modern architecture could be destroyed in the headlong dash for profit.
Since the break up of the Soviet Union, an estimated 400 historic monuments, some dating as far back as the 17th century, have been destroyed. Those buildings which avoid the wrecking ball face a cruel fate: a zealous "restoration" with shoddy materials.
Mr Melnikov says his father's creation was damaged by a botched state restoration 15 years ago, and no one is interested in putting it right. "It's a disgrace. They ruined the orchard outside, and put a concrete seal in the basement rather than bricks, so now it's damp," says the painter, who despite being almost blind and living alone keeps up the house himself on a meagre pension.
Some blame the trail of destruction and neglect on Moscow's mayor, Yuri Luzhkov, under whose powerful administration vast towers and blocks of elite housing have mushroomed on every skyline. Most at risk from the construction boom are avant garde masterpieces from the early 20th century like the Narkomfin semi-collectivised housing complex, Melnikov's house-studio and a series of workers' clubs.
This style of vernacular architecture flourished with the euphoria that followed the Bolshevik revolution in 1917 and the Reds' victory in the civil war and a movement that would synchronise art with life was born. Architects were harnessed to create the ideal living environment for the new Soviet Man: a place where bourgeois forms of domesticity gave way to collective existence.
In this utopia, families would live in harmony in communal dormitories, sharing all possessions - down to their underwear. Nutritionists and childcare experts would take care of chores while citizens were moulded into a single, slick machine. Special rooms were even designated for sexual liaisons.
The constructivists were the vanguard of this movement: "constructors" whose desire was to produce homes, leisure areas and work spaces that derived grace from their practicality. Few of their extraordinary projects got further than the drawing board, but those that did and still stand are precious historical reminders of a hopeful age before communism was eaten from within by purges, war and - finally - stagnation.
"In an ideal world this place would be preserved as a museum," says Valentin Suvurov, 26, a DJ who lives in the crumbing wreck of the Narkomfin complex, behind Moscow's American embassy. "But this is Russia and there's big money involved."
The Narkomfin building was constructed between 1928 and 1930 by the architect Moisei Ginzburg as a "transitional" living space for employees of the ministry of finance. It stopped short of creating the full communal experience, but minimised kitchen areas and encouraged use of a pavilion with shared facilities: a kindergarten (never finished), gymnasium and canteen linked to the block of 56 apartments by a raised walkway.
Split-level apartments provided one sleeping space per family and stoves were designed to reheat food prepared by experts. Its early occupants complained of damp and quickly tired of the communal existence, making personal alterations to their apartments and pleading for larger kitchens. But the building was viewed as a masterpiece and Le Corbusier adopted elements of the design into his famous "unités d'habitation".
Now, after years of neglect, Narkomfin's walls of compacted reed blocks are disintegrating and the strips of horizontal windows on its once seamless facade are choked with weeds. A few weeks ago, the death knell was sounded when a developer stepped in with an offer to buy apartments from the 20 families who live there in semi-slum conditions. A hotel is planned for the site.
A similar fate awaits the Hostels of the Red Professor Institute, across the city, a complex of experimental constructivist housing earmarked for demolition, which are to be replaced by "elitniy" apartments.
"These are creative masterpieces from the most dynamic decade of Russia's 20th century when the country was gripped by an amazing revolutionary fizz," says Clem Cecil of the Moscow Architecture Preservation Society (MAPS), a lobby group that is trying to stem the destruction. "If something isn't done to save them in the next five years they could disappear altogether."
It's not only the achievements of the avant garde that stand at risk. The yen to replace historical monuments with replicas now looms over Catherine the Great's summer estate at Tsaritsyno, on the edge of the capital. The 18th-century brick palace was never finished, but Mayor Luzhkov wants to transform it into a museum - a process that many fear will end in the inevitable chain of demolition followed by "reconstruction".
Aleksei Komech, director of the State Arts Research Institute and a member of Moscow's expert council on architecture, says there is only one determining factor: money. "An entire legal framework exists that perfectly provides for the preservation of historic buildings," he says. "It is simply ignored."
Instead, the process follows a well-worn path. "Imagine a developer comes here and offers to invest in a restoration," he says, sweeping a hand toward the elegant marble pillars inside his institute.
"He has only one condition: let me build a four-storey extension. We agree and approach the Moscow authorities for permission. They say, 'wonderful, fine', only build another four stories for our use." The result, says Komech, is a raft of destructive conversions, with replicas of valuable buildings attached to huge, ugly extensions.
"We are not only losing our monuments, we are losing our city," he said. "At every step, the views and silhouettes of Moscow are disappearing behind these monstrosities."