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There are 8 million mysteries in the Capital City, and at least a few of them can’t be Googled.

Why is there an S1, an S2, and an S4 bus, but no S3? If “Washington” and “D.C.” now mean the same thing, why do we still use both? How much money would it take to persuade Dan Snyder to change his team’s name? Those are some of the questions we received last month when, for the third year in a row, we asked our readers to submit their most nagging queries about life in the District. For this issue, we tackled our favorite 25 submissions, which ranged from the purpose of one of the stranger structures in D.C.’s built environment to the nighttime commutes of its airborne denizens. Questions about animals: We got quite a few of them. (No panda-related ones, though.)

Got a mystery you wish we had unraveled? If your smartphone can’t help you, there’s always The Answers Issue 2015. —Jonathan L. Fischer