When you think of ancient civilizations, you don't usually think of running water or cleanliness. You may instead visualize primitive housing and poor sanitation.

Despite these preconceived notions, this was not always the case. The Indus Valley Civilization in North Southwest Asia (where Pakistan and parts of India are today) life was fairly advanced.

They were particularly advanced when it came to hydraulic engineering and are the first recorded place where flush toilets were used. Many homes had these toilets, which connected to a main sewer pipeline. Most houses had their own wells too. The city walls served to protect against floods.