Mexico is home to various archeological sites, including the ancient city of Izapa in Chiapas.

Now, the Archaeologists from the National Institute of Anthropology and History (INAH) are working on a project to study and restore Izapa, a pre-Hispanic city built with clay, according to an article by Mexico News Daily.

The Mayan city is located on the Izapa River near Tapachula and the Tacaná Volcano, which straddles the Mexico-Guatemala border.

It features more than 30 stone monuments engraved with mythical scenes showing the extensive history of powerful ancient rulers. These carvings haven't been studied for more than 50 years.

The Izapa Research and Conservation Project (PICI) headed by the archaeologist Alejandro Uriarte Torres, aims to restore the splendor of the monuments and the site in general, INAH said in a statement.

Uriarte said that the team is particularly working to repair damage to the site's structures caused by the eruption of the active volcano Tacaná in 1986.

He explained that the PICI team initially examined Izapa in 2015 and found that parts of the clay structures were displaced, crumbling or cracked due to seismic activity linked to rumblings and eruptions at the volcano.

As they were carrying out the restoration work, archaeologists were able to identify the construction systems and materials used at Izapa, one of the most important archaeological sites in the Soconusco region of Chiapas.

Uriarte added that they will conduct a study to determine the source of the materials came.

The research head said all of the structures are made out of clay, explaining that after they were built, their exterior walls were covered with river stones measuring 50-60 centimeters in diameter.

The team also made sure that all of the restoration work has been carried out with respect for the original construction techniques, Uriarte said.

"We learned to value the earthen architecture in Mesoamerica, which is much more common that we think. ... There are a great quantity of sites like Izapa, where only the walls are made with stone ... The whole interior is clay," he said.

"This is something that we have to study more deeply because we generally have the idea that all the Mesoamerican buildings are stone."

Part of the repair work is the cleaning of the stone monuments, or steles, from lichen and other types of fungi that thrive in the humid climate at Izapa that lasts all year-round.

After cleaning, archaeologists take photographs of the monuments to establish a visual registry of their iconography before further deterioration occurs.

Some of the steles were removed from the site before the restoration project began and are on display at the National Museum of Anthropology in Mexico City and the Soconusco Museum in Tapachula.

Museum authorities said a team of biologists from INAH headed by Alejandro Medina, are also studying the microorganisms growing on the steles to determine how they can be removed in the future without harming them.

Historians say that the ancient city of Izapa reached its peak between 850 B.C. and 100 B.C. but was abandoned completely around 1200, when post-classic period of pre-Hispanic Mesoamerica began.