Ancient earthen mounds exist worldwide. Known as "barrows" in England, "kurgans" in Turkey and Russia, and "tumuli" in many parts of the world, earthen mounds are known from:
- Sweden (Gamla Upsalla, 2,000 tumuli)
- Austria (Sulm Valley Necropolis, 2,000 tumuli)
- Hungary (Great Hungarian Plain, 40,000 tumuli)
- Mali (Gorbi Valley, hundreds of tumuli)
- Japan (Kofun Keyhole Mounds, 161,000 tumuli
- Uruguay (Cerritos de Indios, 3,000 tumuli)
Tomb of King Alyattes, Bin Tepe, Turkey |
Earthen mounds are such basic structures they were built by people with relatively low levels of cultural attainment. Case in point: the Aborigines built clusters of tumuli at 10 sites in northern Australia. See Sally Brockwell, "Earth Mounds in Northern Australia: A Review" in Australian Archaeology 63:1 (December, 2006).
North American structures such as those featured in the newly-created Unesco World Heritage Site "Hopewell Ceremonial Earthworks" are generally classified as burial, ceremonial, or effigy mounds.
Limited numbers of people were capable of moving large amounts of dirt. For example, the population of Cahokia in modern Illinois at apogee (ca. AD 1100) is generally estimated at between 15,000 and 50,000 (ancient population estimates are notoriously difficult to determine precisely). This was the largest urbanization north of Mexico in pre-Columbian times. Over a 300 year period (ca. AD 1050 - 1350), this group built the 120 - 190 mounds (reports vary) that made up ancient Cahokia, including 700,000 cubic meter Monks Mound as the centerpiece.
Drone View of Monks Mound, Cahokia Overlooking the Mississippi |
Recent research indicates Monks Mound was built in about 20 years. See this article by the Archaeological Conservancy. Most experts believe the mounds were built by people carrying baskets of dirt. As a quick reality check, I created a spreadsheet with 3 variables:
- Number of people (1,000 - 5,000) carrying baskets of dirt.
- Size of the baskets (1 gallon = 12 pounds, 3 gallons = 36 pounds of dirt).
- Number of trips per day (1 or 2) from the borrow pits to the mound.
Analysis of Time Required to Build Monks Mound, Cahokia |
If 1,000 people made 1 trip per day carrying a 1 gallon (12 pound) basket of dirt, it would have taken 451 years to build Monks Mound. If 5,000 people made 2 trips per day carrying a 3 gallon (36 pound) basket of dirt, they could have built Monks Mound in 15 years.
A modern earthen mound exists in American Fork, Utah, in my backyard. At 16 feet long X 12 feet wide X 8 feet tall, it is large enough to show up on Google Earth. I built it in one day with picks and shovels, assisted by two strong helpers. A landscaper with a Bobcat moved it a few years ago to its present location. My children, grandchildren, and two generations of neighborhood kids have all played on our backyard "hill."
Red Arrow Indicates Mound in American Fork, UT per Google Earth |