Preserving the World'sDigital Memory

The most complex and biodiverse terrestrial ecosystem on earth, containing approximately 10 percent of all species on the planet within 5.5 million square kilometres of living forest, home to approximately 400 Indigenous nations speaking around 300 languages, holding an estimated 150 to 200 billion tonnes of carbon in its biomass and soils, and currently approaching a scientifically projected tipping point beyond which large areas may transition irreversibly toward savannah.

The cliff dwellings of the American Southwest are the architectural achievement of the Ancestral Pueblo people, who built multi-storey stone communities into the vertical faces of canyon walls and under the overhanging ledges of sandstone mesas between approximately 1100 and 1300 CE. Mesa Verde's Cliff Palace, with its 150 rooms and 23 kivas, is the largest cliff dwelling in North America. These were not refuges or temporary shelters. They were planned, permanent communities with sophisticated water management, specialised ritual spaces, astronomical alignments, and long-distance trade connections stretching from the Gulf of Mexico to the Pacific coast. Their builders did not vanish. They are the ancestors of the modern Pueblo peoples of New Mexico and Arizona.

The most extensive low-density urban complex of the pre-industrial world — a religious and administrative capital of the Khmer Empire that at its twelfth-century peak may have supported a population of up to one million people across an urban footprint of roughly 1,000 square kilometres. At its core stands Angkor Wat, the largest religious monument on earth, alongside hundreds of temples, reservoirs, hydraulic works, and urban infrastructure distributed across a landscape that has only recently been mapped to its full extent by aerial LiDAR survey. The hydraulic systems that sustained the city's population are simultaneously its greatest engineering achievement and the focus of its most urgent conservation science.