Lam Chau was not a famous place. It covered just 0.08 square kilometres, its hills barely reaching 100 metres above sea level. Granite formed its bones — the same Hong Kong granite, pushed up through the earth during the Cretaceous period, that underlies much of the territory. Its shoreline was narrow and rocky, its interior covered in scrub. It sat north of Lantau Island and west of its larger neighbour Chek Lap Kok, and together those two islands occupied a stretch of relatively shallow water that planners had long eyed for development. The Pearl River Estuary's western side had space, relatively calm water, and proximity to Lantau — all the qualities that an airport site required. Lam Chau's location, it turned out, was not an accident of geography. It was a factor in its own erasure.

Between 1992 and 1996, one of the most ambitious land reclamation projects ever undertaken transformed the seabed northwest of Lantau Island. The plan was straightforward in concept and staggering in execution: flatten the existing islands, dredge the surrounding sea floor, pile the combined material into a new platform large enough to hold a two-runway international airport with room for decades of expansion. Lam Chau and Chek Lap Kok were both levelled. The sea between them was filled. The new island that emerged covered approximately 12.5 square kilometres — a human-made landform that did not exist before the 1990s, built entirely from what had already been there, rearranged. Hong Kong International Airport opened on 6 July 1998, and its runways now extend over the precise coordinates where Lam Chau once rose from the water.

Navigation charts from before 1992 still show Lam Chau, a small hatched outline west of Chek Lap Kok, properly labelled with its contours and shoreline. Today, that location corresponds to the southwest corner of the airport grounds, close to the western end of the south runway. Pilots landing from the west pass directly over it without any visible trace of what came before. The island exists now only in documents: in older maps, in environmental assessments from the pre-construction surveys, in the records of the Antiquities Advisory Board which catalogued what was there before it was gone. Hong Kong's relationship with its own geography has always been one of active negotiation — the city has been reclaiming land from the harbour since the nineteenth century — but Lam Chau represents a particular kind of erasure, not urban expansion but the deliberate unmaking of an island to build something entirely new.

There is something quietly vertiginous about knowing that a piece of ground you are standing on — or flying over, or landing upon — was not always ground. The passengers boarding flights at Gate 23 or Gate 48 are probably not thinking about Lam Chau. The airport handles tens of millions of passengers a year. Its scale makes the small granite island it replaced feel inconsequential. But Lam Chau was, for however many centuries before the engineers arrived, exactly what it was: a real island with a real shore, birds nesting in its shrubs, fish moving through the rocky water at its edges. It is now the southwest corner of an airport platform. The island and the airport occupy the same coordinates, separated only by time.