The extraordinary Taj Mahal in Agra, India, is a famous symbol of love and devotion. Tremendous wealth was required to construct this monument. There is a direct connection to precious metals of the Incas and their ancestors – and particularly, to silver from the Potosí mine high in the Andes Mountains.
Polynesians living on Easter Island (Rapa Nui) carved enormous stylized human figures known as moai thousands of years after ancient societies built the Stonehenge and Egyptian monuments. Easter Island, formed by three volcanoes that rose out of the sea, contains a variety of volcanic rocks. The ancient carvers carefully selected rocks and carved their statues between about 1250 and 1500 CE. Nearly 900 of the moai can be seen on the island today.
Human footprints found in White Sands National Park, New Mexico, were associated with astonishingly ancient age dates in 2021. New research published in the October 5, 2023 issue of Science reports on two independent age dating techniques that corroborate the third technique. The data show that the footprints are between 23,000 and 21,000 years old. This will require fundamental changes in rewriting our history.
Ancient people made circular arrangements of enormous stones at Stonehenge beginning around 5,000 years ago in the southern part of modern England. Compared with other ancient megalithic monuments in Europe, Stonehenge is unique for the great distances that the builders moved blocks. Archaeologists have shown that quarry locations for some multi-ton blocks are about 140 mi (225 km) distant.
For thousands of years, ancient people collected and transported enormous rocks from quarries to carve their gigantic statues and shape blocks for pyramids, temples, and other monumental structures. The ancient Egyptians are particularly renowned for their work with massive blocks. They used around 200 different quarries over 3,000 years, and worked sandstone, limestone, basalt, granites, and many other types of rocks .
Sand surrounds us–and while it may seem in infinite supply, it is not. Currently, sand is being used up much faster than it is being replenished. Sand and gravel, collectively known as aggregate, are the most widely extracted solid materials on Earth. A recent report by the United Nations Environment Programme recognizes sand as a strategic resource–and one with looming challenges.
The second-most-used substance on Earth is concrete; the first is water. Enormous volumes of cement and concrete are produced each year, and amounts are rising significantly with population growth and emerging economies. Concrete is a major greenhouse gas contributor to climate change, so reductions in this footprint are critically needed.
When I first visited the Peruvian Andes, I was astonished to see groves of eucalyptus — native Australian trees — at elevations greater than 10,000 feet (3,048 m). Eucalyptus is the most widely planted non-native tree in coastal California, which has a Mediterranean-type climate like that found in parts of Australia, but why are these trees in the high Andes?
Geoglyphs are large designs typically longer than about 13 feet (4 m) and produced on the ground by arranging rocks or soil. They are distinctive elements of the archaeological record along the Pacific coast of the Americas, from California to Chile. The Nazca lines of Peru are famous geoglyphs of animals and geometric shapes, constructed in the arid deserts of south-central coastal Peru between about 500 BCE and 500 CE.
Popocatépetl, in southern Mexico, is North America’s 2nd-highest volcano. This volcano has been erupting for millennia—and the recent activity beginning in late May 2023 is bringing additional concern about the possibility of a significant eruption. The tectonic setting of this volcano has some interesting and unusual characteristics.
