There is a long, long distance. "Aztec" ruins are some 2,200 kilometers (1,370 miles) east of Cancun.
However, if you really meant "Mayan" ruins, there are many close to Cancun: the ancient ruins of Chichen Itza are 193 Km (120 miles) east of Cancun; Tulum is some 130 Km (81 mi) south of Cancun, down the Cancun-Chetumal highway.
Cancun is IN Mexico.
Mayan is the answer.
about 1hour
Mayan
Ancient Mayan ruins.
DISTANCE FROM DETROIT,MI,US TO CANCUN,MX 1479 MI/ 2380 KM
approximately 1,375 miles
Approximately 1,375 miles.
Cancun itself has the remains of some small altars scattered throughout the city. However, important archaeological sites are found to the south and east of the city: Tulum and Chichen Itza, respectively.
Merida (capital of the state of Yucatan)Cancun (resort city)Tulum (Mayan ruins)Mayan Riviera (resort towns and villages)Chichen Itza (Mayan ruins)
3 hour drive
2215 miles