Starting from 2023, we have been following sand and water across the Mekong River Basin and outward to Singapore, tracing how materials and lives are bound through extraction, displacement, and infrastructure. Tracing Sand is a pilgrimage for two recovering architects, seeking to reconnect with the fundamental elements of our surroundings—the concrete foundations, the lime mortar on walls, the window glass—all made from sand, drawn from rivers and land in one form or another. At a broader level, architecture emerges from the earth in some way. This ongoing journey is an attempt to unbuild the built environment by attending to its substrata. To unbuild is to reveal how sites come into being: their materials, energy flows, and the socio-cultural imaginaries they inhabit. We take sand as our field guide, as it threads together sites that at first appear disparate: an airport waterfall, river deltas, dredging sites, reclaimed land, and upstream dams. The journey begins at Singapore’s Jewel Changi Airport, where a lush, frictionless spectacle of nature masks an energy-intensive lifestyle built on reclaimed land. Singapore’s thirst for sand leads us into the Mekong Delta, where sinking coastlines, engineered landscapes, and hand-mixed concrete dikes expose the paradox of the immense labour and material demand behind infrastructural promise built on sand. In Phnom Penh, lakes disappear into land, and cities rise as market speculation in its rawest form. Further along, sand is extracted directly from rice fields in Thailand, sorted into commodities under a scorching sun, then carried by barge families whose lives are attuned to tidal rhythms rather than clock time—quietly questioning how much sand a city can absorb. In Laos, sand and pebbles accumulate in resonant mounds, separated by machines and by women’s hands, later reappearing as pristine urban surfaces far from their river origins. The sequence ends upstream, where dams interrupt sediment flows and redirect sand, transforming the watershed into a 'powershed.' Together, these images capture sand as a transboundary agent—circulating through watersheds, economies, labour, and desires—binding landscapes of extraction to spectacles of modernity, and revealing the deep, uneven geographies that underwrite contemporary life.