Surface remains currently cover around 4 square kilometers and include decorated ceramics, monumental structures, and megalithic blocks.

[2] The site was first recorded in written history in 1549 by Spanish conquistador Pedro Cieza de León while searching for the southern Inca capital of Qullasuyu.

Recent studies by geologist Elliott Arnold of the University of Pittsburgh have shown evidence of a greater amount of aridity in the region around the time of collapse.

Twenty-first-century studies have shown that it is an entirely man-made earthen mound, faced with a mixture of large and small stone blocks.

[17] Within many of the site's structures are impressive gateways; the ones of monumental scale are placed on artificial mounds, platforms, or sunken courts.

The iconography of the Gateway of the Sun called Southern Andean Iconographic Series can be seen on several stone sculptures, Qirus, snuff trays and other Tiwanaku artifacts.

Some have claimed that the symbolism represents a calendar system unique to the people of Tiwanaku, although there is no definitive evidence that this theory is correct.

Lastly, Protzen and Nair argue that Tiwanaku had a system set for individual elements dependent on context and composition.

This is shown in the construction of similar gateways ranging from diminutive to monumental size, proving that scaling factors did not affect proportion.

[24] That is, the elites of the state controlled essentially all economic output but were expected to provide each commoner with all the resources needed to perform his or her function.

[27] They were places of worship and rituals that helped unify Andean peoples through shared symbols and pilgrimage destinations.

Although the symbolic and functional value of these monuments can only be speculated upon, the Tiwanaku were able to study and interpret the positions of the sun, moon, Milky Way and other celestial bodies well enough to give them a significant role in their architecture.

The Tiwanaku were highly aware of their natural surroundings and would use them and their understanding of astronomy as reference points in their architectural plans.

[32] According to Incan mythology, Lake Titicaca is the birthplace of Viracocha, who was responsible for creating the sun, moon, people, and the cosmos.

In the Kalasasaya at Tiwanaku, carved atop a monolith known as the Gate of the Sun, is a front-facing figure holding a spear-thrower[33] and snuff.

However, it is also possible that this figure represents a deity that the Aymara refer to as “Tunuupa” who, like Viracocha, is associated with legends of creation and destruction.

The Aymara, who are thought to be descendants of the Tiwanaku, have a complex belief system similar to the cosmology of several other Andean civilizations.

[35] As the site has suffered from looting and amateur excavations since shortly after Tiwanaku's fall, archeologists must attempt to interpret it with the understanding that materials have been jumbled and destroyed.

Other damage was committed by people quarrying stone for building and railroad construction, and target practice by military personnel.

German geologist Alphons Stübel spent nine days in Tiwanaku in 1876, creating a map of the site based on careful measurements.

A book containing major photographic documentation was published in 1892 by engineer Georg von Grumbkow, With commentary by archaeologist Max Uhle, this was the first in-depth scientific account of the ruins.

Von Grumbkow had first visited Tiwanaku between the end of 1876 and the beginning of 1877, when he accompanied as a photographer the expedition of French adventurer Théodore Ber, financed by American businessman Henry Meiggs, against Ber’s promise of donating the artifacts he will find, on behalf of Meiggs, to Washington's Smithsonian Institution and the American Museum of Natural History in New York.

Ber’s expedition was cut short by the violent hostility of the local population, instigated by the Catholic parish priest, but von Grumbkow’s early pictures survive.

[3] Modern, academically sound archaeological excavations were performed from 1978 through the 1990s by University of Chicago anthropologist Alan Kolata and his Bolivian counterpart, Oswaldo Rivera.

Archaeologists such as Paul Goldstein have argued that the Tiwanaku empire ranged outside of the altiplano area and into the Moquegua Valley in Peru.

Excavations at Omo settlements show signs of similar architecture characteristic of Tiwanaku, such as a temple and terraced mound.

Recently, the Department of Archaeology of Bolivia (DINAR, directed by Javier Escalante) has been conducting excavations on the terraced platform mound Akapana.

[41] The program was directed by Gary Urton,[42] of Harvard, who was an expert on quipus, and Alexei Vranich of the University of Pennsylvania.

Over 300 million data points were placed from these methods and have helped redefine main structures that have not fully been excavated such as the Puma Punku.

John Wayne Janusek of Vanderbilt University spent time in the late 1900s as well at the site of Tiwanaku recording findings of the excavations going on.