What are mound builders know for?

Mound builders are known for the various cultures collectively termed "Mound Builders" were inhabitants of North America who, during a 5,000-year period, constructed various styles of earthen mounds for religious, ceremonial, burial, and elite residential purposes.

Explanation:

Mound Builders were inhabitants of North America who, over a period of 5,000 years, built various styles of clay mounds for residential and religious purposes. ... Since the 19th century, the predominant academic consensus has been that the hills were built by indigenous peoples of the Americas.

after the french-indian war.