 Part of the canal is used by the City of Phoenix today.The Olmecs of Mesoamerica built canals over 4,000 years ago.Chinampas, artificial islands constructed in swamplands and lakes, were invented by Mayan farmers and the technique became used extensively throughout Mesoamerica and was later used by the Aztecs as part of the land reclamation process of the city of Tenochtitlan.