You don't have to be religious to appreciate the peaceful atmosphere of Cathedral Church of St. Peter. Look up when the next service is scheduled or when you can go for a wander through.
You'll soon find out why this Helena principal church is visited by many travelers. If you're looking for other things to keep you busy, Montana State Capitol, Carroll College, and Helena Civic Center are in the area too. They won't take you long to get to from Cathedral Church of St. Peter.