The City of Atlantis:

Those who do believe in the existence of Atlantis have formulated      various theories of what Atlantian life may have been like. Regarding the central city, the city of Atlantis was thought to be a bustling Metropolitan center with great bridges and lush gardens as well as universities, laboratories, and other centers of the arts and sciences.  Atlantis is said to have been built in a concentric fashion with rings of land and water forming a bulls-eye pattern. Its core was home to a lavishly decorated temple dedicated to Poseidon and Cleito. However, people who spoke of Atlantis spoke greatly of its people who were said to have been beautiful, ecstatic, and very hard working.

What Atlantis is thought to have looked like

The Countryside:

Surrounding the bustling city was mostly rural farmland, with complex  irrigation moving inland. The general populace was distributed into districts and villages, which were governed by local leaders. It was also up to the leader of each division to recruit men fit for military service.

Atlantis as the Center of Knowledge:

Atlantis was thought to have been the center of knowledge of its time, with advanced technology that was unusually ahead of its time and possibly present technology as well. According to believers, for centuries, Atlantis was the center of the world, in part because of its mighty army and navy which made it too strong to be challenged by another nation. In fact, in his works, Plato, in speaking of the Atlantians says: "They are credited with teaching the Egyptians and the Mayans how to build pyramids and the Greeks how to construct their finely sculpted figures and temples. They are also credited with the invention of reading and writing, mathematics, agriculture, architecture, and all noble concepts of human civilization. It was also believed that the Atlantians were on the threshold of discovering the mystic force behind the Cosmos—and if they had harnessed this force there would have been no limit to human achievements!"

Another Interesting Fact:

Atlantians practiced animal sacrifice in the glory of Poseidon.