This article originally appeared on EightiesKids.com

Michael Crichton based ER on his own experiences as a medical student

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ER was created by best-selling novelist and screenwriter Michael Crichton, who as a younger man had studied at Harvard Medical School, where he earned an MD. The character John Carter, who if you remember began the show as a medical student, was based on Crichton himself, who ultimately chose to abandon his burgeoning medical career in favor of writing.

It was originally meant to be a film rather than a TV show

The original ER script was written by Crichton all the way back in 1974, and was intended to be a movie rather than a TV show. Unfortunately for Crichton (then best known for The Andromeda Strain and Westworld), studios found the material too chaotic, technical and fast-paced, fearing that audiences wouldn’t get it. For this reason, ER was shelved for almost two whole decades.

It got green-lit because of Jurassic Park

Credit: Universal/Amblin

In 1993, Steven Spielberg adapted Michael Crichton’s novel Jurassic Park into the biggest blockbuster movie ever. Spielberg and Crichton subsequently discussed more projects they could collaborate on, which led to them dusting off the ER script. They eventually agreed the project would be a better fit for TV than film, and adapted Crichton’s screenplay into the show’s first six episodes.

George Clooney begged producers for an audition

George Clooney ended the 90s as one of the biggest movie stars and heartthrobs alive, but before ER he was a largely unknown actor who’d spent over a decade searching for his big break. Clooney realized ER and the role of Doug Ross could give him that break, so according to producer John Wells he “showed up and wouldn’t leave until I’d let him audition.”

It was originally written that Carol Hathaway would die in the first episode

Another actor who found fame via ER was Julianna Margulies as Carol Hathaway – but things could’ve been different, as the pilot episode originally saw Hathaway die of an overdose. However, test audiences responded well to Margulies and her interplay with Clooney’s Dr Ross, so this was reworked to instead see Hathaway unsuccessfully attempt to end her own life.

Only the first episode was filmed at a real hospital

ER’s pilot is the only episode to be filmed on location at a real hospital. They shot at the abandoned Linda Vista Community Hospital in Los Angeles, which was operational from 1904 to 1990. The other 330 episodes of the show were filmed at Warner Bros. studios, where a replica of Los Angeles County General Hospital’s emergency room was built.

Noah Wyle filmed an episode whilst suffering from a 104-degree fever

In an unlucky turn of events, ER’s star Noah Wyle fell ill with mono whilst filming ER’s first season. On episode Love’s Labor Lost, Wyle had to act whilst suffering from a 104-degree fever. It was so bad that one of the show’s medical advisers gave Wyle a real saline IV drip, which he kept in his pocket whilst shooting his scenes.

George Clooney played practical jokes on the cast and crew constantly

As well as being a world class hunk, George Clooney is also a notorious on-set prankster. He really developed this reputation on the ER set, where his practical jokes included smearing surgical gel on door handles and phones. “You just hope that George is in the next scene because he’ll keep everybody laughing,” his co-star Anthony Edwards has been quoted as saying.

The famous live episode had to be performed twice – once for the East Coast, once for the West

ER fans will remember the show’s famous live episode, an idea that was actually suggested to producers by Anthony Edwards and George Clooney. Due to the size of the United States, the live episode had to be performed (and broadcast) twice, once for the East Coast and once for the West Coast. An estimated 45 million people tuned into the massively hyped television event.

Eriq La Salle asked producers to end his on-screen relationship to avoid racist undertones

Eriq La Salle’s Dr Peter Benton had several turbulent romantic arcs with other black characters, but his later relationship with the white Dr Elizabeth Corday (Alex Kingston) was much happier and easier. The arc did not last to completion, however, as La Salle asked for the relationship to be brought to an end prematurely, fearing that it might send the wrong message.

The show unintentionally saved the lives of a number of its viewers

While you should never take what you see on a fictional drama as actual medical advice, the writers of ER were very concerned with being medically accurate – and this proved extremely beneficial to some viewers. Allegedly, the producers have files of accounts from viewers whose lives were saved because of something they saw on ER, which helped them react properly in a medical crisis.

The show featured a lot of up-and-coming stars

Many big name actors have made early appearances in ER. In the 90s, Zac Efron, Kirsten Dunst and Shia LaBeouf appeared as child actors, while older actors Ewan McGregor and Lucy Liu also made prominent appearances. Later in 2008, the sadly missed Chadwick Boseman also had a guest role.

Glenne Headly had to hide her pregnancy while on the show

The late actress Glenne Headly had a multi-episode arc on the third season of ER, as pediatric surgeon Dr Abby Keaton. Headly was pregnant when she was cast, and was visibly showing by the time she actually appeared on the show. As a result, she was asked to wear oversized scrubs, and stand behind tables and desks whenever possible, to hide her bump.

NBC thought viewers wouldn’t be able to follow the medical jargon

As ER progressed through the script development phase, executives at network NBC became concerned that audiences wouldn’t be able to follow what was going on given the fast pace and the density of the medical jargon. Ultimately, audiences adored the grounded and slick feel of the fast dialogue, and felt immersed in the world because the actors were talking like real medical professionals.

The first four episodes all begin the exact same way

Until the fifth episode of ER, each show opened with a different core cast member sleeping in exam room eight, until they are woken and told there is a patient on the way. This was abruptly dropped in the fifth episode, after most of the core characters (with the notable exception of George Clooney’s Doug Ross) had been found sleeping there.

Noah Wyle refused one of his character’s romantic arcs

Like Eriq La Salle, Noah Wyle also vetoed one planned romantic story arc, though in Wyle’s case it was scrapped before it even began. The writers had paired Wyle’s Dr Carter with Lucy Knight (Kellie Martin), a medical student who appeared in seasons five and six. Wyle refused, arguing Carter would consider it unprofessional to date a staff member who is technically his subordinate.

Chicago Hope began just a day before ER premiered

When ER premiered, it had a direct rival in Chicago Hope, another medical drama on CBS. Both shows enjoyed comparable success for a time; though ER scored consistently higher ratings, Chicago Hope wound up taking home more Emmys for its cast.
In the end, ER had the greater longevity, running for 15 seasons while Chicago Hope only ran for six.

George Clooney had a ‘trick’ for remembering his lines

If you ever noticed Doug Ross glancing down at charts, holding a clipboard or reading in any other capacity, that’s because Clooney would write his lines down on the many charts and pieces of paper he carried with him. Clooney started doing this to help remember his lines while working on ER and movies back-to-back, and other cast members soon followed his example.

All the key original cast members appeared in the show’s final season

ER is considered such a career highlight for most actors that the entire core cast returned to be there for the show’s final episodes, despite many of them having left seasons before. Anthony Edwards, Noah Wyle, George Clooney, Eriq La Salle, Sherry Stringfield and Julianna Margulies all appeared in season 15, even if they couldn’t stick around for very long.

The show began and ended with the same two words of dialogue

ER’s very last episode echoes the very first in an interesting way. The words ‘Dr Greene’ ended up being both the first and the last line spoken in ER, although they actually referred to different characters each time. In the beginning, the Dr Greene in question was Mark Greene, while in the last episode it is his daughter, Rachel Greene, that is being addressed.

It famously crossed over with Friends

As two of the most enduringly popular shows of the 90s, ER and Friends had a number of quasi-crossovers, even if they never did anything that could be considered canon. Both shows appeared on NBC on Thursday nights, which is why it was arranged that George Clooney and Noah Wyle would both appear on Friends, playing doctors (though not technically their characters from ER).

Laura Innes’ fake ER injury caused her real medical problems

Laura Innes’ character Dr Kerry Weaver has congenital hip dysplasia, which caused her to walk with a limp. However, a full decade of having to walk with this limp impacted Innes physically; constantly miming a limp had in fact curved her spine. Because of this, ER season 11 saw Dr Weaver have hip surgery, and after recovering from this she no longer limps.