Archaeologists have discovered the oldest evidence yet of a wooden structure crafted by the hands of a human ancestor. Two tree trunks, notched like Lincoln Logs, were preserved at the bottom of the Kalambo River in Zambia. If the logs' estimated 476,000-year-old age is correct, it means that woodworking might predate the emergence of our own species, Homo sapiens , and highlights the intelligence of our hominin ancestors. Archaeologists unearthed the logs at Kalambo Falls, on Lake Tanganyika in northern Zambia, a site that has been investigated by scientists since the 1950s. Previous excavations around a small lake just upstream…