There are several ancient ruins in the southwestern part of the US. Colorado, Arizona, New Mexico all have places you can visit. They are very interesting places to visit. Near Cortez, CO there is the Mesa Verde Ruins. In Farmington, New Mexico there are Salmon Ruins. Aztec Ruins in Aztec, New Mexico . Chaco Ruins, somewhere near Bloomfield or Chaco Canyon, New Mexico. Canyon De Chelly, Arizona has Cliff Dwelling Ruins. They are all known as the "Ancient Anasazi Ruins".
Yes, there were Spaniard Warrior Empires found in Southern Texas.
The Folsum man's bones were found in the southwest of the USA. The remains were dates to 15,000 years ago. Along the Mississippi River valley, human-made huge earthern mounds have been found on the riverbanks. In the Florida Keys, large mounds of harvested sea shells are in place indicating Native Americans collected food there.