It was probably an unintended consequence of television that it killed the circus.

Actually, TV didn’t kill every circus. It just undermined Ringling Brothers and Barnum & Bailey, America’s alpha circus for close to a century.

Now, just a year after Ringling Brothers and Barnum & Bailey turned out its lights for good, its story is told with colorful, fascinating detail in The Circus, a two-part, four-hour documentary that airs Monday and Tuesday at 9 p.m. ET in the PBS American Experience series (check local listings).

The Circus suggests that almost everything you need to know about American whims, wishes, instincts, and pleasures was embodied in the glory days of the circus, which peaked in the late 19^th century and the Roaring '20s.

P.T. Barnum, the showman who signed on to promote a small circus and ended up owning the one that defined and shaped the whole industry, was the best known American of the 19^th century, The Circus suggests, much as Babe Ruth might be the best-known American of the 20^th.

Like most good promoters, Barnum was a smooth liar, capable of saying anything that would win an audience at the moment. It’s a trait you’d think we’d find tiresome, except we can see in our own times that we’re just as likely to reward as to rebuke such promoters.

One of the few matters about which P.T. Barnum did not lie: He did indeed create “the greatest show on earth.”

At its peak, the circus traveled from city to city in a railroad train with more than 100 cars. It had a thousand employees whose jobs ranged from helping raise the Big Top to defying death on the flying trapeze.

Toss in the lion tamer, the elephant procession, the tightrope walker, the acrobats and all the rest, and you have an afternoon or evening that transported spectators into a glamorous world where their only obligation was to sit back and marvel.

The Circus, written and directed by Sharon Grimberg, sets an almost fantastical goal of its own: explaining why, among all forms of entertainment since the nation’s founding, none captured our attention like the Big Top.

That romance, alluded to and affirmed all over popular culture and oral tradition, was partly rooted in our fascination with things that make us gasp. It also sprang from a deeper potpourri of wishes and desires that include our admiration for the wanderer, the person who lives in constant motion.

Running away to join the circus, for many decades, was the quintessential American escape. When a young Bob Dylan arrived in New York in the early 1960s, he made up tales of traveling with the circus as a fast albeit fabricated means of branding himself as someone who had blown in the wind.

The Circus spends some time on the realities of life among circus performers, from the artists to the roustabouts who signed on to handle the massive nuts and bolts of the operation.

They worked hard, often for grievously low pay, and they lived on the move. Come to town, set up, then a few days later tear down and head for the next town. Performers here recall that they were given two buckets of water a day, one for washing and one for rinsing, and that this showering, like everything else, was done communally.

This turned the circus into a rough-edged family, and like all families, it engendered every shade of drama from friendship to rivalry. It was life some loved fiercely, and others found hard – and all that, The Circus suggests, fed into the passion that permeated the show itself.

In the larger picture, we’re reminded of what we now see as great cruelty toward the exotic animals of the circus. We’re reminded of the “freak shows” and the display of essentially kidnapped natives from around the world as dangerous “savages.”

We’re reminded that P.T. Barnum, James Bailey, and the five Ringling brothers earned millions on the backs of their modestly paid and segregated workers – and that their skill at knowing how to make those bucks shaped much of American entertainment, right up to television itself.

The variety show on which early television built much of its following was largely an abbreviated adaptation of the circus.

Eventually, The Circus suggests, the outsized Barnum & Bailey concept simply outgrew its economics. The Depression was a serious blow. The 1944 Big Top fire in Hartford, which claimed 168 lives, was another. By the time TV rolled around, The Greatest Show on Earth was on the downhill side of its glorious run.

It folded the Big Top in 1956 and continued as an arena attraction until 2017.

The Circus notes that Ringling Brothers and Barnum & Bailey was never the only American circus. Numerous smaller circuses operate today, focusing on acrobatics and other physical feats rather than parades of elephants or freak shows.

But Ringling Brothers and Barnum & Bailey was the defining circus, the spectacle against which others were measured, and The Circus argues persuasively that its exhilarating decades reflect our love for daring adventure – not to mention our capacity for tolerating outlandish hype as long as the perpetrator keeps us entertained.