The Pyramids of Teotihuacan are a must-see when visiting Mexico City. Wear comfortable running shoes as there is a lot of walking and climbing (to the tops of the pyramids). There are some gift shops close to the site and there are some Tequila making shops nearby. Buy some of the almond flavored tequila - it is amazing!

Teotihuacan is a short drive from Mexico City proper and, in my opinion, is totally worth the ride. I visited before a Wal-Mart was built within view of the pyramids, but a visit now is still a good way to see ruins without going as far as Chichen-Itza. Climbing the pyramids is a challenge, but the view from the top is beautiful, and you can tell how much work went into constructing the site. A short tour provided good information about how the site used to look (where houses and markets were, etc.), and we took time to explore on our own. There is a small touristy market by the exit and various vendors walking around who may bother you, but simply ignore them or tell them you aren't interested in their wares and continue exploring. If you can only climb one pyramid, scale the Piramide del Sol, the bigger of the two.

One of the most impressive archaeological sites in the Americas, Teotihuacan flourished until 750 AD when it was abandoned. When the Aztecs arrived, they recognized the site's formidable history and named it Teotihuacan which means a place where gods are born. The Avenue of the Dead (Calzada de los Muertos) was named as such because the Aztecs believed the soul travelled in a north-south direction (like the avenue) on its way to the afterlife. The Pyramid of the Sun measures 225m on each side and 70m in height, almost as large as the Great Pyramids of Giza (231m base). At the north end of the Avenue of the Dead, lies the Temple of the Moon which was built directly over a cave in 2nd century AD. Caves were generally considered places where gods and ancestors emerged, as well as doors to the underworld. Only 46m high, it still affords great views over the city and countryside. It is easiest and cheapest to go with a tour guide. Bring food and lots of water and slather on the sunblock.

In the side of the pyramid of the Moon you will find a small area, you have to climb some steps to get into the Temple of Butterflies "Quetzalpapalotl"—named because of the decoration carved in the columns and patio.

Everything here is original, walls, columns, paint and even the stucco floor, so they ask you not to use high heels out of the wood walkways. The stucco is dyed red, and just looks like it was plastered last year—it´s in such good conditions it would be a shame if you damage it.

The columns have carved pictures of butterflies and birds, some of them still have the eyes made of obsidian—a local precious stone that is black-grey and shines in the same way a hologram viewed from different angles.

After you finish visiting the patio, don´t go back to the pyramids or Deads Row. Instead, go down to your right and enter the subterranean passages where you will find the real housing complex and some excellent murals.
The mural depict everything from animals (a parrot is easy to spot), to flowers, and complex geometrical shapes. All the city was decorated with colorful murals. It is a shame that we always think about ruins as just stones piles together... these weren´t.

Everybody aims to climb the highest pyramid in Teotihuacan, unfortunately the temple at it´s top is no longer there, but you can visit a very short pyramid (not climb it), is not the Moon (the second largest) but dedicated to a guy with feathers, Quetzalcoatl, the Feathered Serpent God.

He is also known as Kukulcan in the Mayan areas, but here in the central area of Mexico, is associated with Tlaloc God of Rain, whose representations are unequivocally with some kind of goggles, which is unique, only him wears them no matter if in Teotihuacan, Chichen Itza or Copán (Honduras).

In the pyramid you find a richly decorated facade where you will find the head of the serpent with a collar of feathers, and also the end of the snake, the rattle, along with some faces of Tlaloc, corn and sea shells, the latest are not indigenous to this area.

Teotihuacan was a contemporary of Copán, Calakmul, Palenque, Tikal and many other Mayan cities, the trading and influence is overwhelming as the archaeological records show, the architecture and pottery of the Central America zone changed radically after Teotihuacan´s conquest or cultural invasion, we don´t know yet.

Back to the pyramid. Now is off limits but years ago you were able to walk just a few inches from the amazing carvings, today there are important excavations going on and also some restoration works, so sadly you have to climb the small platform built to, guess, cover the pyramid from view at the Citadel. It´s believed that for some reason Quetzalcoatl felt from the favor of the ruling elite at some point because the whole pyramid was obscured from public view (but not destroyed, interesting). The traditional way to honor a building was to build a bigger one on top of the first, without destroying the decoration or murals, but in this case no one has come with a reasonable explanation.

The Citadel is in the farthest south area of the archaeological complex near the old museum, so many tour companies just skip it in order to take you directly to the Sun and Moon complexes and gain more time to take you shopping (all of them get a commission at the stores), but you will miss a great opportunity to admire the facade of this pyramid, make sure the guide will take you to this one. The walk from one end to the other is a long one, it will take you more than 20 minutes under the hot Sun, so is better to go by car.