By RICH GRANT

With 25 million visitors a year, New York’s Central Park is the most popular green space in the United States – and the most recognizable. More than 200 films have been shot here. From romantic “Annie Hall” to blood-ridden “Death Wish,” from tender “Love Story” to brutal “Fatal Attraction,” Central Park is one of the biggest Hollywood movie sets in history.

But while Central Park may look familiar, most of the millions who come here have no idea what they are seeing.

As they stroll down some 58 miles of shady paths through a landscape of rolling lawns, trees and lakes, populated above by 250 species of birds, they have little awareness that they are walking through one of the great urban wonders of the world. For this lovely park of a half million trees and plants is entirely manmade.

When the idea for a park was first proposed in 1844 by newspaper editor William Cullen Bryant, New York had a population of 500,000 people, most living in crowded and cramped conditions. Bryant wanted a public park that would offer families a place to escape for carriage rides and give working-class New Yorkers a “healthy alternative to the saloon.”

By 1853, the city had spent $5 million to buy 6 percent of Manhattan Island – a parcel of land a half-mile wide by 2.5 miles long. The land was basically worthless. It was filled with swamps and rocky outcrops, as well as being home to some 1,600 poor Irish pig farmers and 3,000 African Americans, all of whom would have to be relocated.

There was no public landscaped park in America at this time, so in 1857, a landscape design competition was held to decide what to do with all this space. The winning design, submitted by the park’s superintendent, Frederick Law Olmsted, and an English born architect and gardener, Calvert Vaux, called for creating pastoral landscapes reminiscent of English paintings filled with rolling meadows and deep woods, offset by huge public spaces where the elite of New York could gather and stroll on terraces. Commercial roads through the park would be sunk nine feet deep so that bridal paths and walks would go over them uninterrupted on a series of 36 bridges.

Building the park became one of the most massive construction projects in New York history. Twenty thousand Irish workers labored for 15 years. More gunpowder than was exploded at Gettysburg was used to blast out mountains of rock, while an estimated 10 million horse-drawn carts rolled into and out of the park, dragging away debris and swamp and bringing back rich topsoil from New Jersey. Ninety-five miles of pipe were laid underground to feed the six manmade lakes, reservoirs and streams, while European craftsman created seven splashing, ornamental fountains and German gardeners planted a quarter million trees and shrubs. Finally, 9,000 benches (seven miles of seats) were placed near ponds, overlooks and in wooded glens under stately elms.

In its first decades, the park was a place for the wealthy, who arrived by carriage in top hats to stroll the Mall. But as poor immigrants moved north on Manhattan, eventually surrounding the park, its character changed. By the 1970s, Central Park was one of the most dangerous places in the city with every building covered by graffiti, while park benches were missing their slats and garbage and litter were everywhere.

Then, in 1980, control of the park was given to the Central Park Conservancy. To date, this private, nonprofit organization has raised more than $500 million and restored Central Park to the brilliancy of the original design by Olmsted and Vaux. A team of nearly 50 gardeners keep the 843 acres in immaculate condition. Today, the park is safe, spotlessly clean and litter-free. Amazingly, all 125 water fountains work, while the restrooms play classical music.

There are maps posted throughout the park, filled with photos of nearby attractions to see. One feature asks cell phone users to call (646) 862-0997. Touch tone the extension posted at different sites and you can hear celebrities describe what you are seeing, from Whoopi Goldberg talking about Wollman Skating Rink to Jerry Seinfeld telling jokes about the Mall.

There are bike tours, bike rentals, walking tours, pedi-cabs and surprisingly inexpensive horse-drawn carriage rides. But the best advice to experience the park is to just wander, get hopelessly lost and look for these treasures along the way:

The Pond and Gapstow Bridge

Similar to the Ponte di San Francesco in San Remo, Italy, this graceful stone bridge is an icon of Central Park and the subject of many postcards. The banks of The Pond are lined with flowers; the reflection of the nearby skyscrapers make this one of the park’s most visited spots.

The Mall

One of the grandest elm-lined walkways in the world, the Mall is a four-block-long pedestrian promenade where you’ll find many of the park’s 51 statues.

Bethesda Terrace and Fountain

The “heart of the park” is this ornamental fountain and terrace. Two sweeping staircases lead down to a terrace, where the gentry of New York once came be seen. Today, it is a great people-watching spot and home to world-class street performers. Nearby, the Boathouse is one of the city’s most romantic restaurants. They also have an inexpensive outdoor bar, the perfect place to enjoy a beer by the lake.

Strawberry Fields

On Dec. 8, 1980, John Lennon was shot dead as he entered his home at the Dakota Apartment Building at 72nd and Central Park. The former Beatle loved walking in the park with his wife and young son. Through the generosity of his widow, Yoko Ono, a 2.5-acre parcel of the park was re-landscaped and named Strawberry Fields, in honor of the Beatle’s song, “Strawberry Fields Forever.” From Yoko’s 7th floor apartment in the Dakota, the area looks like a giant teardrop. Ten thousand tiles from Italy spell out a simple mosaic with just one word: “Imagine.” Strawberry Fields opened on Oct. 9, 1985, which would have been John’s 45th birthday. Today, music fans gather here every year on that date.

Bow Bridge and the Lake

Another classic movie location, Bow Bridge was completed in 1862 and was built entirely of cast iron. The 22-acre lake is best seen by row boat, with looming skyscrapers in the background.

The Ramble

Just north of the lake, walk under the picturesque Ramble Arch into a maze of trails and paths through a forest-like woodland, with streams and waterfalls. Though it looks wild, every single thing was planned and planted. Olmsted wrote: “Every foot of the park, every tree and bush, every arch, roadway and walk, has been fixed where it is with a purpose.”

Belvedere Castle

Designed in 1865, this castle offers breathtaking views over the Great Lawn and is an entry way to the Shakespeare Garden, a quiet place in the park where the only plants are flowers that were mentioned in Shakespeare’s plays.

The Obelisk – Cleopatra’s Needle

The oldest monument in the United States was erected in Heliopolis around 1500 B.C. and moved by Rome’s Augustus Caesar to Alexandria in 12 B.C. Depending on who you ask, it was either given to the United States as a token of good faith or stolen by William Vanderbilt, but in 1879 it came to New York and was erected near the Metropolitan Museum of Art, which sits nearby at 81st Street.

Jacqueline Kennedy Onassis Reservoir

This 106-acre reservoir is 40 feet deep and holds a billion gallons of water. The 1.58-mile running track along its edge is one of the city’s favorite jogging spots.

Conservatory Garden

This hidden gem at Fifth Avenue and 105th Street is actually three gardens based on classic English, French and Italian designs. Filled with fountains and flowers, walkways and tree-shaded paths, it is the only formal garden in Central Park, and one of the park’s most secret and deserted retreats.

More information

Central Park also has a famous zoo, two skating rinks, a Shakespeare theatre, the famous Tavern on the Green restaurant and the equally beautiful Loeb Boathouse restaurant, four inexpensive outdoor cafes and the Conservatory Water, where in the children’s classic book, the little mouse Stuart Little had his famous boat race and where New Yorkers sail model boats on the weekend. And that’s just the beginning.

For more information, check out the Conservatory’s website and the Central Park website.