Archery ranges, bathhouses, beaches, boating, camps, conservatories, driving ranges, indoor firearm ranges, golf courses, gymnasiums, ice-skating rinks, boating, marinas, music halls, polo fields, pools, riding academies, stadiums, and zoological and botanical gardens in the P-1 Park District, provided that the lot area is not less than three acres and all areas of operation and associated structures are not less than 50 feet from any lot line.