A ziggurat is a type of rectangular temple tower or tiered mound erected by the Sumerians, Akkadians, and Babylonians in Mesopotamia. The tower of Babel is thought to be one of these.
A pyramid is a massive monument with a square base and four triangular sides; begun by Cheops around 2700 BC as royal tombs in ancient Egypt.
Pliny the Elder, writing in the first century AD, describes a religious ceremony in Gaul in which white-clad druids climbed a sacred oak, cut down the mistletoe growing on it, sacrificed two white bulls and used the mistletoe to cure infertility. The druids appear in Welsh and Irish legend as prophets and sorcerers. Oaks were held sacred by both druids and Celts.