Archaeologists think El Meco (Av. López Portillo s/n, 8 a.m.–3 p.m. daily, US$3.50) was a major gateway to and from Isla Mujeres —fitting considering it’s located just north of the modern-day ferry terminal at Puerto Júarez.
The ancient city seems to have thrived in its role as port town, building the tallest pyramid along this part of the coast before collapsing abruptly around A.D. 600. It was reoccupied four or five centuries later, probably as an outpost for the powerful Chichén Itzá  kingdom.
The site is smaller than El Rey , in the Zona Hotelera, but the structures are more substantial.