TMAP's collection of bottle openers, many of which are shaped like places you've heard of.
First, I draw them in CAD, then I have them cut in Seattle out of different thicknesses of steel. I deburr them and tumble them to give them a uniform finish.
The thin, stainless steel ones are a bit rougher on the hands than the thicker mild steel ones, but weigh half as much. You may be surprised by how substantial the 1/4" ones are. They're still completely pocketable, but they can double the weight of a ring of keys. Choose wisely.