All because we took a different exit from the metro

Generally speaking, metro stations on Milan's Yellow Line are the only ones with elevators. This comes in handy pretty often -- the consulate is on the Yellow Line -- but it also means I tend to take certain routes because they're easier.
But yesterday I decided I'd carry Owen and his stroller up the stairs at the Missori station instead, and we ended up in Piazza Missori. I've been there numerous times but never had seen the gate to the crypt of San Giovanni in Conca open. This time it was, though, and we decided to descend into its depths.
The church doesn't really exist anymore; this, which was the apse, is all that's left at ground level:An aside: This is the kind of pose one gets after instructing their preteen to "look like you actually want to be here."
So, I'd seen this little piece of Romanesque ruins tons of times but not the crypt. I was so glad we happened by when it was open. One of the volunteers working -- the Touring Club of Italy mans many of Milan's free sites -- took us around to explain all of the photos, illustrations and maps, as well as a section of aqueduct that also happened to flow through the crypt. I understood much of what he told us but wondered why the church had been torn down. (One of the photos, from 1885, shows the campanile with scaffolding on it.) My later research showed that much of the building was razed to make way for Via Mazzini (in 1879) and then was reduced to its current tininess in 1949. But the Waldensians, who owned it by then, used the facade on their new church.
So now I guess I need to go find THAT, as well as pay more attention the next time we're in the archaeology section of the Sforzesco Castle musuem, where most of the real artwork from San Giovanni in Conca now resides.