"Only a dollar" is their opening offer, for here, unlike in most of the rest of Mexico, American dollars (or at a pinch Canadian) are the currency of choice.
When you say you're not from America or Canada they will, as a last resort, take Mexican pesos.
But even the crowds, the stalls, the heat and the humidity cannot lessen the grandeur of this archaeological site - the tall, stepped central pyramid, the court where the mysterious and often deadly (for the losers) ball game was played, the other ruined temples and buildings, and the sacred cenote, or sinkhole in the jungle.
This part of the Yucatan has no rivers or lakes, so these deep sinkholes in the limestone bedrock, filled with water from underground rivers, are the only source of fresh water.
The ancient Maya laboriously hauled it up in gourds or pots, a mind-boggling thought when you consider the huge resources and manpower required to build the magnificent cities that dot this and many other parts of the country.
About 100km away, around the less crowded and perhaps more beautiful ruins of Uxmal, the soil is more fertile but there is no water above or below ground. People stored rainwater from the annual wet season in large underground cisterns.
A sound and light show brought home to us their desperation when the rains were late or insufficient.
No wonder they devoted such huge resources to supplicate the rain god, Chaac.
When their prayers were not answered, or as modern commentators suggest, their use of resources became unsustainable, they abandoned this city, as they did many others.
Magnificent and elaborately carved as they are, the pyramids and ruined buildings at Chichen Itza and Uxmal pale into insignificance compared with the huge Pyramid of the Sun and the Avenue of the Dead in Teotihuacan in the upland Valley of Mexico.
Despite the name, recent investigations suggest this pyramid too was dedicated to the rain god, known as Tlaloc in this part of the country.
It's not surprising as in Mexico there seems no lack of sun, but water was obviously a problem.
Sitting in the huge metropolitan cathedral in Mexico City, I couldn't help pondering the huge resources those in power dedicated to propitiating their gods - and no doubt demonstrating their supremacy and inspiring awe and dread among the common folk, neighbours and enemies at the same time.
Started in 1573, only 50 years after the Spanish demolished the Aztec city of Tenochtitlan on which Mexico City is built, the cathedral stands testament to the same impulse in the Spanish conquerors.
They built many churches, cathedrals and palaces on the sites of indigenous temples, using the stone of the buildings they were replacing.
These are grand edifices in the European style of the day, many with elaborate baroque gold or silver altar pieces, carvings, paintings, and other ornamentations that still have the power to astonish those who see them.
Death has preoccupied people in this part of the world perhaps more than most - from Aztec and other prehispanic human sacrifices, through the many images of the suffering, crucified Christ in colonial churches, to the festival of the Day of the Dead, when Mexicans go to cemeteries to remember friends and family members who have died.
It's not hard to see the similarity between the rows of skulls carved on the ruins of some of the Aztec temples or the idea that they kept skulls of dead relatives in their houses, and the candy skulls and decorative skeletons that are part of the Day of the Dead celebrations.
It seems old traditions don't die, they just change and become absorbed in new ones.
Like the Mexicans themselves, a blend of indigenous and Spanish, to the observant visitor religion in Mexico seems an amalgam of many prehispanic deities and practices mixed with the saints and rituals of the Roman Catholic Spanish colonisers. Nowhere is this more obvious than at the Basilica of the Virgin of Guadalupe, the most loved and honoured saint in Mexico.
In 1531, only 10 years after the Spanish conquest, an Indian peasant, Juan Diego, saw vision of the Virgin Mary on the hill of Tepeyac.
She appeared as a mestizo, a blend of indigenous and Spanish, and told him she wished a temple to be built there in her honour.
The bishop did not believe Diego.
The church authorities suspected it was a ploy to reinstate the worship of Tonantzin, the Aztec mother earth goddess whose temple on the site had been destroyed by the Spaniards.
It took several miraculous signs from the Virgin, including providing out-of-season roses and imprinting her image on Diego's cloak, before the authorities finally agreed.
Now churches, shrines and gardens form a pilgrimage complex on and below the hill of Tepeyac.
The old basilica, sinking dangerously on its foundations, was replaced in the 1970s by a modern circular building that seats 40,000.
High above the altar hangs the well-known image of the Virgin of Guadalupe, said to be the original image on Diego's cloak, and the most revered relic in the country.
Despite the Mexican revolution in the early 20th century, when many churches were stripped of their ornamentation, the new constitution which reduced the Catholic Church's political influence, and modern secular life, this basilica and its surrounding complex is the most visited pilgrimage site in the country.
Locals, some of whom are so devout they enter on their knees, come to pray and, of course, tourists come to take photographs and tick the basilica off their list of places to visit.
