The Day The Earth Caught Fire (1961, Val Guest)
Edward Judd tries to get off with a posh bird whilst the world goes to shit. Leo McKern has hair!
Vaguely remembered this from childhood and was suitably impressed as an adult. Packs more detail into 100 minutes than any Marvel (or modern Hypocritewood film tbh) schlock.
Even if the "riot" made me cry with the laughter, this will be getting the revisit sooner than laterer.