Manitoulin Island. Separating Georgian Bay from the rest of Lake Huron, it is the largest Freshwater Island in the World. Largest Island in a Lake. Contains the largest lake in a Lake (Lake Manitou, 104sq mkm). Contains the largest Island on a lake on an Island in a Lake (Treasure Island in Lake Mindemoya, on Manitoulin Island, in Lake Huron....Treasure Island reputedly contains several ponds).
http://en.wikipedia.org/wiki/Manitoulin_Island
http://en.wikipedia.org/wiki/Lake_Manitou
http://en.wikipedia.org/wiki/Lake_Mindemoya
http://en.wikipedia.org/wiki/Treasure_Island,_Ontario
Location of Treasure Island:
http://maps.google.ca/maps?hl=en&biw...&ved=0CIYBELYD
http://www.blacksbay.com/activities/hiking.html
I visited last year, but I am too lazy to post photos.