I recently saw a Twitter post about Columbus reaching (discovering) Bahamas and not knowing where he was. First response was:
""The first europeans to see it" is an accurate statement, yes. It's just silly and eurocentric to say "Europeans 'discovered' a continent filled with millions of people that had several cities as large or larger than the largest cities in Europe."
I dont want to discuss semantics if it is possible to discover something that already exist, even if you are not aware of its existance, but I am genuinely curious about statement about large cities in Americas? I tried to google, but I could not find any accurate estimates.
At its height in the 12th century CE, the city of Cahokia (just outside of what is now St. Louis, Missouri, United States) would have rivaled many large old world cities in population.
In addition to Cahokia, there were a few other pre-Columbian cities that rivalled European cities in size, though not all of these were at their peak in the late 15th century.
At the time of the Spanish Conquest, Cusco, the capital of the Inka Empire, had 40,000 people living in the city and 200,000 in the surrounding area, what we might think of today as the "metropolitan area". At its height the city proper had as many as 150,000 people. Other Andean cities which had previously hosted relatively large populations were Huari (up to 70k), Chan-Chan (up to 60k), and Tiwanaku (up to 20k).
Tenochtitlan, the capital of the Aztec Empire, was even bigger. Its population in 1519 was estimated to be between 200,000 and 400,000 people. Mesoamerica was full of smaller urban centres that had flourished in previous eras. Examples include El Pilar (180k), Caracol (140k), Tikal (100k), Coba (50k), Calakmul (50k), and Chichén Itzá (50k). Most of these population maximums are from the Classic Maya period, their highest populations reached several hundred years before Europeans arrived.
The Amazon rainforest is believed to have been home to several large cities in the pre-Columbian and early colonial periods. However, we only have one account of these cities from a firsthand observer, and his population estimates are not completely reliable as he describes the cities more in terms of their size than their population density. Archaeologists are starting to recover evidence of the mounds that some of the most important buildings in the cities were built on, but it's not enough to give us an estimate of their population.
For comparison, here are the 10 most populous European cities in the year 1500:
Spain's largest city at the time was Granada (70k), Portugal's was Lisbon (60k-120k) while England's was London (50k-100k). So while no city in the Americas had populations exceeding the most populous cities of Europe in 1500, several of these largest cities were not where the primary colonizers came from (i.e. Spain, Portugal, France, and England). Of these countries' cities, only Paris may have had a larger population in 1500 than any pre-Columbian city had ever reached.
Many of the pre-Columbian cities discussed above would have been at their peak more around AD 700, such as the Classic Mayan cities or Tiwanaku and Huari. The three largest cities in Europe in 700 were Constantinople (100k-800k), Rome (40k), and Paris (20k-30k). Except for Constantinople's higher population estimate, these are much smaller numbers than we find in Mesoamerica and the Andes at the time. This shows that there were absolutely periods in history when the Americas had larger urban centres than Europe did.
As you can see, comparing Europe and the Americas' urban centres side by side is complicated, since the two continents urbanized at different paces. Some places which had once been very urban had become less densely populated by the time of European arrival. It's also important to keep in mind, of course, that these are all fairly rough estimates determined mainly by archaeologists, though in Europe there are sometimes economic records to help fill out the picture.
Even so, at the time of European contact, Cusco and Tenochtitlan were larger than any European cities except Constantinople and possibly Paris.
To add to the great comments here already: in 1803 Philadelphia became the largest city north of Mexico. Unbeknownst to the them, the previous largest city north of Mexico was Cahokia 800 years earlier. Always love sharing that fact as I think it really drives home how large Cahokia was and how impressive it truly is as a site. For context, the United States was formed as a nation with no cities larger than Cahokia.