In 1954, for some inexplicable reason, the windows behind the altar were bricked up. Everyone blames the 60's for starting the wreckovation trend, but it really started in the 50's.
Photo courtesy of Alex Fries.
UPDATE: I've been informed that the priest there, at the time, thought the windows were distracting. The pictures he had stencilled up there weren't? Now we have a few priests who think the tabernacle's a distraction of it's behind the altar, but who think having the choir and a whole bloody friggin' rhythm section, back there, is perfectly in keeping with the situation. Let's not even get into how distracting a blank wall can be.