Conímbriga, Portugal (Roman ruins)

Conímbriga is the most well preserved Roman settlement in all of Portugal. 
The layers of the archeological site date back to the 9th century. 
​Remarkably preserved mosaics and building structures can be found in numerous locations around the ancient city.
It is estimated that only 10 percent of the city has been excavated.
The site also has an impressive museum that contains artifacts that have been discovered there.