Whoever wrote the caption on the back of this 1940s postcard understood this well.

“Spectacular sight as this is typical of all New York which is truly a fairyland when night begins to descend,” the caption reads.

“The Empire State Building, guardian of the skyscrapers, keeps faithful watch over her charges throughout the night.”

But not the 42nd Street at the turn of the last century, as this circa-1900 photo, from New York Then and Now, demonstrates.

That year, the midtown block of 42nd Street between Fifth and Sixth Avenues was a still-residential stretch of muddy Belgian blocks, a single gas lamp, and horse-pulled streetcars.

“The horsecars were run by the 42nd Street, Manhattanville and St. Nicholas Avenue Railway as a crosstown line between the Weehawken ferries at the west terminal and the Hunters Point Ferry to Long Island City at the east end,” the caption tells us.

The church on the right is the West Presbyterian Church, and the el tracks on the left won’t be torn down until the 1930s.

By 1974, almost nothing remains, and West 42nd Street looks much more familiar to contemporary eyes.

“The building with the curved front is the Grace Building, built 1970-1972 on the site of Stern Brothers Department Store, which stood here from 1913 to 1969, having previously operated on West 34th Street for 36 years,” reads the caption.

Today, 42nd Street looking toward Sixth Avenue reveals more glass office buildings, a replica of an old street lamp, plus many of the same buildings from 1974—such as the Grace Building and the Gothic-like entrance to 11 West 42nd Street.

It’s not in the photo, but I imagine Bryant Park, which would be on the left, looks very different—this park had a bad reputation until the 1980s.

No one was taking there lunch break or watching movies on the lawn then!

A plaque outside the three-story brick house on the southwest corner of Irving Place (right) and 17th Street identifies it as the one-time home of Washington Irving.

Though it’s debatable whether Irving actually lived there, a bohemian power couple of late 19th century did.

Actress-turned-interior designer Elsie de Wolfe (left, in 1880) and Elisabeth Marbury, a literary agent, met in Paris.

There they lived openly as a couple before returning to New York in 1892 and renting the Irving Place house.

The two cheekily called themselves “the bachelors” and hosted Sunday afternoon salons with an eclectic array of celebrities of the day.

Among the guests were Oscar Wilde, Ethel Barrymore, Stanford White, and Sarah Bernhardt, all sipping tea and mingling with New York’s old money society.

“From 1897 to 1907, Bessie and Elsie’s house was a salon famed for its fascinating artists, writers, and performers,” writes Cherie Fehrman in Interior Design Innovators 1900-1960.

“People came because, in the words of millionaire William C. Whitney, ‘you never know whom you are going to meet at Bessie and Elsie’s but you can always be sure that whoever they are will be interesting and you will have a good time.’”

The salons ended, perhaps because de Wolfe’s decorating career had taken off.

She’s credited as being the first interior designer ever, transforming dark Victorian interiors into lighter, airy living spaces and publishing the pioneering book A House in Good Taste in 1913.

In 1926, de Wolfe shocked society by marrying a British diplomat. She became known as Lady Mendl; a tea parlor currently operating on Irving Place called Lady Mendl is a nod to her salon-hostess past.

[Photo above: Irving Place and 17th Street in 1905. Right: Elsie and Bessie in later years]

But the bronze statue of a girl holding roses in her right hand and a butterfly sundial in her left is an especially captivating sight.

Called “Roses of Yesterday” and created in 1923 by Harriet W. Frishmuth, the five-foot statue fittingly welcomes visitors into the rose garden pavilion.

Frishmuth was a Philadelphia native who came to New York to create art. She had a studio on Sniffen Court, the loveliest alley in Murray Hill.

But the population of Harlem was already changing, from mostly Irish and Jewish residents to African-Americans.

By the 1940s, the building, located on 160th Street at the edge of the posh Sugar Hill neighborhood, was exclusively black.

Sitting high on a bluff and commanding gorgeous views of the treetops of Edgecombe Avenue and across the Harlem River, these 13 floors plus a penthouse were home to Harlem’s elite.

That included academics, entertainers, and athletes such as Count Basie, Joe Louis (below), Sonny Rollins, sociologist Kenneth Clark, and Paul Robeson (above).

And though today it’s officially within the borders of Washington Heights, 555 Edgecombe is historically identified as part of Harlem.

It’s not an especially distinctive building architecturally, but it is handsome and sturdy, an emblem of the neighborhood’s prime years as a center of artistic and activist achievement.

[Photo right: Property Shark]

This generic deli awning on the corner at 21st Street doesn’t conceal the previous tenant, the perfectly straightforward Chelsea Wine & Liquor Company.

A little further up the same side of the street is this old-school signage for Chelsea Merit Florists (minus the final two letters).

Another sign tells us they’ve been in business since 1930—but these days, the Merit is gone from the name.

Funeral Designs—interesting service to advertise on a storefront!

Built in the 1760s by British colonel Roger Morris as a breezy hilltop retreat called Mount Morris, it was used as a headquarters by George Washington during the Revolution. (Yep, Washington really did sleep here!)

In 1810, wealthy couple Stephen and Eliza Jumel turned it into a French-inspired country home, where they entertained prominent residents of the young city.

After her husband died, social-climbing Eliza’s new spouse, Aaron Burr, moved in—a fascinating story for another post.

Anyway, two hundred years later, the Georgian-Federal style mansion is a museum. But perhaps the most interesting relic is a slab of stone on the grounds outside the house.

It’s a mile marker. Before GPS, maps, and even a city street grid, mile markers were set in the ground on roads outside the city. They let travelers know how far they were from today’s downtown.

This mile marker says we’re 11 miles north, not a short distance back in the day.

An accompanying plaque explains that the mile marker was originally placed in 1769 on Kingsbridge Road, which ran along Broadway, according to Myinwood.net.

Mile markers have been disappearing for generations. Apparently a nine-mile marker remained in Upper Manhattan until as recently as 1991.

As far as I know, there’s only one other mile marker left in the ground: this beauty on Ocean Parkway in Brooklyn. I hope it’s still there.

I always imagine hundreds of turtles sunning themselves on the rocks along the East River between 45th and 48th Streets.

That’s where the actual bay was once located in Colonial-era Manhattan, surrounded by meadows and hills, with a stream that emptied at the foot of today’s 47th Street.

Click on the map for a bigger view; it was drawn in 1878 to accompany a book about New York during the Revolutionary War.

But while turtles were plentiful in Manhattan (and made for a tasty meal), the name may come from a corrupted Dutch word.

“Some historians attribute the name to the turtle-filled creek, while others say it had nothing to do with turtles, that the name was more likely a corruption of the Dutch word “deutal” (a bent blade), which referred to the shape of the bay,” states the Turtle Bay Association.

“Regardless, the turtle feasts of the day prevailed and so did the name, Turtle Bay Farm.”

Not the Hudson, a site about the East River, has a more definitive answer.

“It was named after the Deutal (Dutch for “knife”) Bay farm, which originally covered 86 acres of land shaped like a knife blade. Also occupied by turtles, historians are unsure as to which one of these factors resulted in the name.”

If it was named for the shape of the bay, it no longer applies. The “rock-bound cove” that sheltered ships from storms was filled in and smoothed over in the 1860s.

The Beekman mansion—known as Mount Pleasant (left)—once stood at the northern end of Turtle Bay; it was demolished in the 1870s.

The United Nations occupies most of the site now.

But a handful of tenements buck the trend and appear to be named for a man. Is it the developer himself, or just a random name that happen to appeal to circa-1900 ears?

I wonder if that’s the case with Jerome. It’s the name of a tenement in Morningside Heights, perhaps a nod to Leonard Jerome, a flashy 19th century financier whose name still graces a park and thoroughfare in the Bronx? He’s also the grandfather of Winston Churchill.

Theodore, on the Upper East Side, could be a tribute to Theodore Roosevelt. Or the builder’s son or brother?

The Roger, on 160th Street and Edgecombe Avenue in Washington Heights, is named for Roger Morris, a British army colonel who fought in the French and Indian War.

In the 1760s, he retired to an Upper Manhattan estate (now known as the Morris-Jumel Mansion) that still stands today.

I don’t know who Edgar was or why a tenement on West 125th Street was named for him. But instead of the name being carved above the door, it’s laid in tile on the floor.

The name change has to do with a gruesome murder near this intersection in 1873, then the media attention that gripped the block for the next few years.

In March, Charles Goodrich, a 41-year-old widower, was found with three gunshot wounds to the head in his brownstone at what was then 731 Degraw Street.

At first, police thought it might be suicide or a robbery. But strangely, his body had been laid out neatly and cleaned of blood.

So when neighbors reported that a young woman had been living in the house and that they often saw Goodrich with her on the stoop, police took the investigation in a new direction.

They believed the woman’s name was Kate Stoddard (right); she was a Massachusetts native in her 20s who worked in a hat factory in Manhattan. But for months, she proved to be elusive.

Finally, after a sighting by Stoddard’s ex-roommate on the Fulton Ferry, cops tracked her down.

During questioning, she denied everything—until detectives found Charles Goodrich’s personal items in her room in a boarding house on High Street.

Reportedly she confessed. Turns out her real name was Lizzie Lloyd King. She’d met Goodrich through a personal ad, and they soon married.

Then Goodrich told her the marriage was a sham and he wanted her to leave him alone, as he was now engaged to another woman.

During an argument in the house on Degraw Street, a spurned King drew a gun and shot Goodrich dead.

In 1874, she was committed to an upstate insane asylum for life—but not before residents of Degraw Street between Fifth and Sixth Avenues  (left) petitioned the city to have the street’s name changed, fearing the “unpleasant associations” with the murder.