Complex sentence: Don Mills is a residential neighbourhood in Toronto, Canada, and claims to be the first "new town" planned and fully integrated post-war community developed by private enterprise in North America, and the blueprint for post-war suburban development in Toronto and contemporary residential neighbourhoods.
Split into simpler sentences: Don Mills is a new town and neighbourhood in Toronto, Canada, recognized as the first planned and fully integrated post-war community developed by private enterprise in North America. It is credited with being the blueprint for post-war suburban development in Toronto and contemporary residential neighbourhoods.