The document summarizes three landmarks from early civilizations and their importance:
1. Paleolithic cave art from 40,000 years ago which showed early religious beliefs and animal depictions.
2. Stonehenge, a massive stone structure from 4,000 years ago in England, that may have been an astronomical calendar and helped unite Britain's people.
3. The Great Pyramids of Giza, precisely-constructed pyramids from 2,500 BC that marked royal burials in Egypt and had astronomical alignments detectable only at equinox sunrises and sunsets, showing the Egyptians' knowledge of the earth's movements.