"That is the name of the street we are under."
Translation:Tak se jmenuje ulice, pod níž jsme.
I am not far enough along in the course to be SURE that your construction is okay (though I think it may be), but "tohle" would be "this" rather than "that."
This sentence doesn't make much sense, unless you are navigating in the sewers.
Or you ride the subway.
That said, navigating the sewers was actually not that rare until they destroyed most of the geocaches after the death of several people in an accident in Prague in 2018.