Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE architect (Id VARCHAR)
TABLE: CREATE TABLE mill (type VARCHAR, architect_id VARCHAR)

### Question ###
What are the distinct types of mills that are built by American or Canadian architects?

### Accurate SQL ###

SELECT DISTINCT T1.type FROM mill AS T1 JOIN architect AS t2 ON T1.architect_id = T2.id WHERE T2.nationality = 'American' OR T2.nationality = 'Canadian'