The San Francisco door.

Mrs. Guess had lived at 1474 Pine Street in San Francisco for nearly 50 years. The home had belonged to her grandparents as a proper home before they made the financial decision to split it into apartments and to take in renters. There was a sense of loss having a home that wasn't truly and entirely your home but the income it generated in these crazy times of such extremely high rents suited her well enough.
Her later years were very comfortable. No worries about money and the best apartment on the sunny side of the street left her without many pressing needs. Because of this she found herself becoming more curious about life around the world. No fewer than five magazines a month found their way to her door all of which brought her stories of different cultures and glorious pictures of places she would probably never see except for in their pages.
With so much to read about concerning places around the world it was very easy to ignore what was right in front of your face. Especially if it was something that had been right in front of your face for over fifty years. Directly across the street from Mrs. Guess's private patio between two townhouses was a door. This was not uncommon in the city since homes were pushed up close to each other leaving a continues wall of buildings from one block to the next.
As common as it was to have a door like the one across the street and as common as it was to see it and not see it on a daily basis this morning the door did something very uncommon today. It opened. Then something happened that Mrs Guess realized had not ever seen happen in the entire time she'd lived on Pine Street or for the entire time she'd even been in the home visiting her grandparents. Someone came out of the door.
Its seemed queer to realize you've never seen anyone exit or enter a door you've seen every day for over half a century. But what happened next struck Mrs. Guess as even more queer. The person who exited on to the street, a man by the looks of him, did something very queer himself. He looked surprised. Gave a quick look around smiled so big surely his face would split in two then walked down the hill towards the financial district.
Why would he be surprised to find himself on the street like that? Mrs Guess wondered to herself. Why had she never seen anyone go in and out of that door? She never gave it much though but if she had assumed anything about the door she would probably have assumed it was an alley door between buildings. What had changed though? And why was she suddenly so curious about that door?