EDINBURGH, Scotland — In long-ago days this venerable town was known — oddly, affectionately — as “Auld Reekie.”

It’s believed the nickname came, in part, from the smell generated as residents of yesteryear greeted each new day by opening their windows and flinging the contents of their chamber pots into the street below.

This was before indoor plumbing, if you get my drift.

Founded in the 12th century, bordering a marsh and clustered around its castle fortress for safety, Edinburgh in its early days built upward instead of out — creating a crowded warren of five- or six-story apartment dwellings, the skyscrapers of their day (many of which still exist). From that height the, er, flingings could have devastating impact on a wayward pedestrian.

But this sunny spring morning in Scotland’s capital, my wanderings are relatively safe. My objective: exploring Old Town’s fascinating network of narrow walkways and alleys between those crowded buildings. Most alleys are known by the Scottish term “close.”

Some are no more than dimly lighted tunnels where passers-by brush shoulders between walls of ancient cobbles or roughly hewn bricks. Think of Seattle’s Post Alley, especially the narrow bit where you find the Gum Wall. Narrow it by three-quarters, make the entrance an ancient stone archway, and you have the idea. Great places for exploring with camera in hand.

And they all have names. Historically, a close would be named for a prominent occupant of a bordering building (such as Stevenlaw’s Close, named for Steven Law, a supporter of Queen Mary during the Civil War of 1571) or a business (such as Fleshmarket Close, named for a slaughterhouse, not a brothel). Or it might take its name from its location, such as the tellingly named World’s End Close, historically the last close before reaching the original town wall (which encompassed, for many medieval townspeople, their world).

Often, I discover on my walk, a bronze plaque on a wall will explain the name of a close, which might go under variant names such as “wynd” or court.

A close may be a simple passageway from one street to another. Sometimes it will include steep stairways between levels of the hilly town. Occasionally, you’ll discover a secret nightclub, a dramatically framed view across the city, or colorful doors to hidden dwellings.

Down Advocate’s Close, where Lord Advocate Sir James Stewart lived from 1692 to 1713 (a plaque tells me), I am surprised when a white-haired gentleman, nattily attired and walking with a cane, suddenly bids me “good morning” after emerging from a wooden door above which crumbling masonry bears the inscription, “Blissit Be God of Al His Gifts” (sic). There’s also a date: 1590.

But even as in olden days, do watch your step. Sometimes locals are less than careful about cleaning up after their dogs in the dim confines of closes. “Auld Reekie” still has its reekie bits.