Dr. Louis Leakey with Homo Habilis
In August 1960, Dr. Louis Leakey, a British-Kenyan paleoanthropologist, discovered the skull shown here on the right next to the skull of a chimpanzee, in the Olduvai Gorge in northern Tanzania, Africa. Leakey later identified the skull as that of Homo habilis, meaning "handy man," because he believed that his specimen had been a toolmaker. Although anthropologists disagree on the interpretation of the fossil, it is universally acknowledged as a significant discovery.
The Leakey's Fossil Discoveries
Louis and Mary Leakey, left, and their son Richard, right, are noted paleoanthropologists whose research in the Olduvai Gorge in East Africa advanced the study of human evolution. In Tanzania Mary Leakey discovered a series of fossils that were over 3,600,000 years old, which provided evidence supporting her claim that human evolution began much earlier than other scientists had believed.
Female Homo erectus Skull
Fossils of tools and the skeletons of large mammals found near fossils of Homo erectus, or "upright man," suggest that these human ancestors led more complicated lives than earlier species. Although the anatomical structure of this species resembles that of modern humans, anthropologists have found that the human brain underwent many changes during the evolution from Homo erectus to modern humans. Anthropologists believe that Homo erectus lived between 1.5 million and 0.3 million years ago. This skull belonged to a female Homo erectus of the Beijing type.
Skulls of Prehistoric Humans
Neandertals were primitive ancestors of modern humans who lived in Europe and North Africa between 75,000 and 40,000 BC. They were hunter-gatherers who had brains somewhat larger than those of modern humans. German anthropologists Johann Fuhlrott and Hermann Schaaffhausen first found Neandertal fossils in 1856 in the Neander Valley near Düsseldorf, Germany. The skull of a Neandertal is shown here between that of Pithecanthropus (left) and Cro-Magnon (right).
Gaius Julius Caesar
One of the most influential political and military leaders in history, Gaius Julius Caesar helped establish the vast empire ruled by Rome. Caesar’s triumph in a civil war in the 40s BC made him the absolute ruler of Rome, but political jealousies among his opponents motivated them to assassinate him.
Victims of Mount Vesuvius
Once a thriving city in ancient Italy, Pompei literally disappeared with the eruption of Mount Vesuvius in AD 79. After a devastating earthquake in AD 63 decimated the city, Vesuvius emitted poisonous gases into the atmosphere and covered Pompeii with ash and mud. The ash mixed with rain and settled around the volcano’s victims, creating molds that remained intact long after the bodies had decayed. Archeologists poured liquid plaster into the forms, preserving the exact shapes of the bodies at the moment of death.
Ruins of Pompeii
In AD 79, the ancient volcano Vesuvius erupted and rained hot ash, stones, and cinders over the city of Pompeii, located a mile away. About 4 m (13 ft) of ash covered the city, which remained buried for more than 1500 years. Archaeologists began excavating Pompeii during the 18th century, finding the remains of people, ancient buildings, and other artifacts preserved amid the volcanic debris. Among the structures uncovered was The Forum of Pompeii, pictured, a group of temples, courts, and palaces that served as the city’s legislative center.
Considered one of the most important inventions in history, the wheel is more than 5000 years old and has been crucial to mechanical devices ever since it emerged. The wheels shown here are relatively sophisticated in comparison to the earliest models. In the case of a fixed axle, the wheel is held in place beside the chassis by a small peg and revolves independent of the axle. (This model differs from another standard design, the moving axle, in which the axle is firmly fixed to the wheel and the two components revolve as a unit.) Early forms of roller bearings, devices that help wheels to turn more smoothly, were developed around 100 BC. Wheels were initially solid disks, but gradually evolved into the spoked design, which is both light and strong.
Machu Picchu, Peru
The ruins of Machu Picchu, near Cuzco, are the remains of an ancient city of the Inca Empire. The civilization, based in southern Peru, dates to 1200. The Inca mastered architecture, road building, and astronomy and were noted for their code of laws and advanced system of government.