Short answers, pulled from the story.
The Olmec civilization developed in the swampy lowlands of modern-day Veracruz and Tabasco around 1500 BC. This environment featured well-watered alluvial soil within the Coatzacoalcos river basin which supported dense populations.
The largest Olmec colossal head measures over nine feet tall and weighs between 25 and 55 tonnes depending on calculations. These monuments were carved from single blocks of volcanic basalt found in the Sierra de los Tuxtlas.
San Lorenzo Tenochtitlán was abandoned around 900 BC following widespread destruction during the 950s BC. La Venta rose to prominence after this decline and lasted until its own abandonment around 400 BC.
A farm worker discovered the first colossal head labeled Tres Zapotes Monument A in the late 1850s while clearing forested land. José Melgar y Serrano visited the site in 1862 to complete partial excavation and publish his findings several years later.
Mitochondrial DNA studies from 2018 confirmed that Olmec ancestry lies within indigenous American populations rather than Africa. The results disproved claims made by Ivan Van Sertima regarding African origins based on facial features.