If, as Walter De Maria once suggested, 'Isolation is the essence of Land Art',¹ then his Broken Kilometer (1979) and New York Earth Room (1977) might be said, albeit in a rather perverse way, to be quintessential examples of the genre. Of course, there is much to distinguish the pieces from what we conventionally think of as land art.

Most obviously, unlike the specific work De Maria was discussing in his text - his own Lightning Field (1977), situated in desolate rural New Mexico - they are located not near some mesa deep in the lonely heart of the American West, but rather in one of the most heavily trafficked parts of the urbane American East. Among the longest-term residents of New York's SoHo district, the projects have for more than 20 years occupied two pieces of prime real estate in the heart of one of the city's most notoriously changeable neighbourhoods.

Yet familiarity, as it often does in the world of art, seems to have bred a kind of contempt for Earth Room and Broken Kilometer. Despite - or indeed, precisely because of - their stubborn longevity, the two pieces have become, for all intents and purposes, invisible. Sporadically visited, staffed by solitary gallery assistants at silent desks, the works are truly 'isolated', a solitude made more dramatic and poignant by the fact that, thirty feet away and oblivious to their existence, thousands of people swarm each day past the boutiques and bistros that have come to dominate the area. As one colleague said, 'Could there possible be a place less conducive to thinking about the "land" than a Manhattan art gallery?'