Duluth has an incredible number of parks and green spaces: well over 100 according to the official city list.
Some of the major parks are featured in the city's new virtual tour space. 

Stay up-to-date on happenings in the Duluth Parks  via their FB page.

2015 Summer Concerts Schedule at Chester Bowl Park.

Comment: it could be interesting to create lists of parks by activity, for example "Parks with bike trails", "Great parks for hiking", "Parks with waterfalls", etc.