Toronto Lost Rivers Walks. 328 different areas and buildings and more across the city in their subjects.

 
 Parkdale walk, http://www.lostrivers.ca/ParkdaleWalk.html
Text from the groups site,
The objective of Lost River Walks is to encourage understanding of the city as a part of nature rather than apart from it, and to appreciate and cherish our heritage. Lost River Walks aims to create an appreciation of the city’s intimate connection to its water systems by tracing the courses of forgotten streams, by learning about our natural and built heritage and by sharing this information with others.
The Toronto Green Community started Lost River Walks to help us discover the fascinating world of the watershed beneath our feet.
Subject count list May 19 2019