The Carthaginians discovered the Americas in 508 BC, exchanging European and American diseases and foods. American crops, potatoes in particular, disrupted the Roman economy, which no longer relied on Egypt as a breadbasket. Rome fell early, and African civilisation did considerably better. After the Black Death struck meso-America in 1361, the Tenochca became dominant.
Now, in 1848, an industrial Aztec empire is a major world power and busy colonising Europe.