Of course, architectural works created specifically for communal sporting events are one of the most enduring of forms that have survived down through the years.
We spoke in passing of the Roman Arènes de Lutèce in Paris, which is now in this condition - an impressive artifact, even as a partial remnant:


Because it is August, and a hot one at that, our conversation drifted again and again towards baseball.
One of the grand-daddy ball fields we spoke about is Wrigley Field, in Chicago:

with its lovely ivy-covered outfield walls:

We also spoke of the old(er)-fashioned design of Camden Yards, in Baltimore:

And grand old Fenway Park, in Boston:
As compared and contrasted with the new Yankee Stadium, with seating for 74,000 (!) fans:


We also discussed the possibilities for new sports buildings, perhaps even with new sports events - how fan spaces for witnessing, say, a lacrosse game with 1,000 players might comprise floating fan seating in blimps, or how the Quidditch pitch of Harry Potter lore, is a new sort of stadium design, never seen before. Here, a Quidditch stadium from one of the Potter films, with its high towers:

And, last, we spoke of the newly-proposed Brooklyn Velodrome - images of which will be forthcoming as soon as I - your host (and architect) - have completed the schematic design! Stay tuned!
Speak with you next time!
Best,
Curtis B Wayne