There is something magical about Grand Central Terminal. Perhaps it’s the large windows or the vaulted ceiling or the people scurrying around the central axis of the clock perched in the middle of all the chaos. For me, it’s the aqua-and-gold-colored depiction of the night sky’s constellations. The colors are pure and vibrant, and they lend the space a kind of incandescence. It wasn’t always this way. Before the interior’s restoration–completed in 1998–the ceiling and surfaces were grimy, stained with decades of tobacco smoke and dirt. The restorers left a reminder of the ceiling’s previous condition–a patch of grime left untreated in the northwest corner of the open-air terminal, right neat the Cancer constellation. It’s a vow to never again let the building deteriorate to such a state.