The pyramids of Teotihuacan, located just outside modern Mexico City, is a vast complex that was abandoned for over 1000 years when the Aztecs migrated into the region in the 14th century AD. Archaeologists have recently found a tunnel 40 feet below the foot of the Temple of the Plumed Serpent (mentioned in an earlier post) and many artefacts were dug out of the ground. At its peak the city was home to 100,000 people – but it was suddenly abandoned around 200AD (or a bit later). The story was in the London Times newspaper but it is the time-scale that is interesting from a catastrophic viewpoint. The Aztecs arrived in the 14th century at around the time of a climatic downturn in NW Europe, a switch to a very wet period. This implies changes in the Jet Stream and therefore the Intertropical Divergence Zone, possibly leading to drought in some regions of the subtropics. It is also worth pointing out that the plague occurred in the late 14th century – although it is not thought to have affected the Americas.
Likewise, when Teotihuacan was abandoned, around 200AD, or perhaps a bit later, we also have a downturn in the fortunes of the Roman Empire and their contemporaries in Europe and Western Asia – but dated around 240 to 270AD. This event also appears to have affected Gupta India and contemporary China – so we are talking in terms of a global event of some kind.