Abstract Ancient human footprints have been known from Managua, Nicaragua, since the 1880s. The main footprint site, long preserved in the Acahualinca Tracks Museum ( Huellas de Acahualinca ), reveals hundreds of human footprints that represent a minimum of 12 clearly defined trackways and a trampled trail or path. Deer, opossum and bird tracks are also present at Acahualinca, and bison and tapir tracks have been documented from the nearby and stratigraphically equivalent El Recreo site. The age of the Acahualinca footprints is controversial, but the best current estimate is about 2–2.2 ka BP. The Acahualinca site is one of the most scientifically important human footprint sites known from the Holocene. It exhibits footprints that are very abundant, well-preserved, accessible for study and part of a large sample that demonstrates variation within a single population. The Acahualinca site has historical, cultural and archaeological importance in preserving at least two intervals of human occupation, that of the footprints and of the ceramics in much younger layers. Its significance to anthropology and palaeontology as a sub-fossil footprint locality is clear and the volcanological history of the area is intimately related to determining the age and the circumstances of footprint registration at Acahualinca. The Acahualinca footprints merit geoheritage status.

Abstract While Olduvai Gorge, Tanzania, is most famous for its impressive and formative record of early human technology, Pleistocene fauna and hominin fossils, its geological record is equally important. At Olduvai, palaeoanthropologically significant sites are often preserved in primary context (not redeposited), and they can be contextualized within the palaeoenvironments in which the hominins lived. This has provided an exceptional opportunity to assess not only hominin evolutionary changes over time, but also to understand their adaptive behaviour including toolmaking, foraging and sociality. Abundant volcanic material from the nearby Ngorongoro Volcanic Highlands, interspersed within and between archaeology-bearing deposits, made Olduvai a target for some of the earliest applications of radiometric dating using the K/Ar system. Ultimately, the 40 Ar/ 39 Ar dating system has produced ages with exceptional precision. Early radiometric dating at Olduvai helped establish the antiquity of the hominin lineage, and early palaeomagnetic studies (and the ‘Olduvai event,’ the longest normal subchron within the reversed Matuyama Chron) were critical in establishing the importance of Olduvai in the field of geochronology. More recently, high-resolution palaeoclimate studies of the palaeolake that once occupied the Olduvai Basin have helped to reconstruct the palaeoenvironments encountered by hominin species. Over a century of geological research has secured Olduvai's status as an important site for geoheritage.

Abstract Social development and rapid growth in the world's population has followed a remarkable technological development the past hundred years. Revolutions in agriculture and industry, medical innovations and new production technologies, have led to an increased standard of living for a larger part of the Earth's population. Megatrends for future developments are lining up and predictions for the next 40 years are numerous. Most ideas about our future societies imply new and innovative geo-scientific achievements. Towards 2058, we will have virtually surveyed and mapped every corner of the Earth. We will have detailed 3D images of the urbanized areas, and 4D models to assist to make reliable forecasts in a world of increased pressure on the natural resources and changing ecosystems. By 2058 the Green Stone Age is established, and we will use all elements in the periodic system and more rare minerals to support new materials and technological solutions. The major energy supplies will be CO 2 free. The agriculture will be more efficient, distribution and consumption of food will be more rational, and we will harvest from more marine food chains than today. More than 70% of the people on Earth will live in megacities and urban areas. Our cities will become smarter and greener, cars and public transport will be self-driving and autonomous tools using artificial intelligence to automate functions previously performed by humans. Substantial resources will be used to repair damaged ecosystems, and most important, we will use materials and products that have fewer negative consequences for the environment. The 17 UN goals for sustainable development are guidelines into the future, and geological surveys should serve as key instruments in the transformation into smarter and more sustainable societies. We are already on our way providing critical minerals for low carbon energy solutions, marine knowledge for blue growth, plans for green and smarter cities, and advanced digitalization for public services, as shown by examples in this present paper.