The Huellas de Acahualinca (Footprints of Acahualinca) are among the oldest known human traces in the Americas — a set of prehistoric footprints preserved in volcanic sediment on the western shore of Lake Managua, within the city limits. The prints, dating to roughly 6,000 years ago, show a group of perhaps ten people walking along what was then a mudflat, their feet sinking into the soft volcanic ash before it hardened over millennia.
The site is now a small, well-presented museum built over the original find. You can look down at the actual footprints through a glass floor, and the exhibit explains the context with geological and anthropological detail. It is not a large museum but it is genuinely fascinating — standing above prints left by people walking this same ground six thousand years ago has a particular kind of power. The site is in the older western part of the city, a short taxi ride from the lakefront plaza.