What was one major achievement of the Inca Empire?

The conquering of most or all of present day Peru. (Pachacuti). They had the early form of brain surgery.

Explanation:

These are some achievements I remember.

north atlantic treaty organization.

necessary and proper clause. the congress shall have power to all laws which shall be necessary and proper for carrying into execution the foregoing powers, and all other powers vested by this constitution in the government of the united states, or in any department or officer thereof.