When you walk the streets of New York City, it’s almost impossible to not be a voyeur, even if inadvertently.

Maybe you glance through a ground-floor window and your gaze lingers a little longer than it should because the twinkle of a chandelier catches your eye. Or maybe the crisp lines of a doorman’s uniform make you pause or maybe it’s the gentle hand he proffers to help an elderly resident cross the threshold.

This week, our Voyeur pays homage to something that can be easily overlooked in our living environment: doors. Even though they stand between us and the chaos of the city, doors can blend seamlessly into the cityscape. Here are a few that stopped us in our tracks.

Have an idea for some place or something the Voyeur should explore? Send it to realestate@nytimes.com.