Galleria Umberto in Boston’s North End is generally lost among Boston’s better-known pie shops like Santarpio’s and Regina. That’s curious, because, as put forth a few years ago by one Gadling.com travel blogger, it may very well be one of America’s best cheap slice places. But the fact that it’s somewhat under the radar is probably preferable to the locals, because as it is, there’s already a line outside the door for these thick, over-the-edge-of-the-pan cheesy, saucy, completely over-the-top Sicilian slices. That’s right, the Sicilian is the only pizza option, and the joint is cash only. Though it opens at 11 a.m., it closes at 2:30 p.m. (or whenever the dough is gone), so don’t delay.