The word acropolis simply means 'high city' in Greek. Many old Greek towns had one - a hill in the middle where people built their most important buildings, because hills are easier to defend and you can see them from a long way off. The Acropolis in Athens is the most famous one in the world.
The Parthenon was built between 447 and 432 BC - that is around 2,500 years ago. Imagine 25 great-grandparents standing one in front of another, and the one at the back was alive when it was being built. The Greeks used hammers and chisels and ropes; no cranes, no electricity, no power tools.
The whole temple is made of marble - shiny white stone quarried from a mountain ten miles away. Workers cut huge blocks weighing many tonnes and pulled them up the hill on wooden sledges. Every column is made of stacked stone drums, fitted so cleanly together that you can hardly see the joins.
The Greeks built the Parthenon to honour the goddess Athena, who in their old stories was the city's special protector. The city is even named after her. Today, no one worships there - it is a place that millions of visitors come to look at and learn from each year.