Having tried an alternative compiler, Algol 68 Genie, it's an incredibly fun exercise – like riding a 60s' concept car; weird, overdesigned and overcapable, and simultaneously hilariously impractical, but fun, fun, fun.
Two fun features: semaphores as a language construct, as well as a block for parallelized statements.
But... but... C is 53 years old also, it is still rarely called out by its age