If we're doing befores and afters, here's Lansdowne Park.
First, Lansdowne Park(ing lot), which was roughly its state between 1967 and 2012. It was never really a park in its entire history from 1868 to 2012, but mostly open ground with a few buildings for the Central Canada Exhibition and other events.
https://app06.ottawa.ca/calendar/ott...%20doc%201.htm
And since 2014.
https://fotenn.com/project/lansdowne-redevelopment/
Lansdowne 2.0 will see the 10k Civic Centre Arena/North Side Stands demolished. A new 5k arena will be built east (park side) of the stadium, new North Side Stands where they are now, and a retail podium and towers over the site of the current Civic Centre.
No improvements to the actual Park portion have been presented so far.