What makes the United States multicultural

they celebrate many cultures as well as have different cultures

People of the different countries and different region who migrated and settled down in America makes the United States as a Multicultural nation.

Explanation:

United States has a long history of Migration where first the Americans (initially slaves) demanded their right to live in America properly without being discriminated on the basis of rights provided by the constitution.

After that the Germans and then Chinese, Irish and other Eastern Europeans migrated to United States. People with different culture and different religion thoughts make United States as a Multicultural nation.