Not just one of the best episodes of its season, or of the show as a whole, it was an episode of television so powerful it merited a full breakdown of its creation 25 years later. It breaks down just how fragile health is, and how even doctors like Greene (Anthony Edwards), amazing at their job, can make small mistakes with devastating consequences for others as much as themselves.

This high-drama episode focusing on Dr. Ross vaulted George Clooney from mere actor to superstar, paving the way for his eventual jump to movies. It was also the series' first major foray outside the walls of the ER, with all the tension and claustrophobia the writers could wring from the cramped tunnel location.

In the show's first exit of a major character, we say goodbye to Susan (Sherry Stringfield) and get a sweet ending to her and Dr. Greene's sort-of not-quite relationship. There's a wedding, a divorce, and another fling for Carter with Glenne Headly's Dr. Keaton.

A major event episode, with a chemical spill forcing every core character (with the exception of poor Kerry Weaver) into dramatic situations, including exacerbating the Doug and Carol (Julianna Margulies) drama by leaning in to that cliché of television clichés: Trapped In An Elevator. Still, it's high-wire and gripping television.

Sure, there was Doug Ross's dramatic exit in parts 1 and 2 of '"The Storm" and the swirl of "The Good Fight," but at least once a season the show would step out of the hospital to let us get to know a character in a more meaningful way. Season 5 takes us to Mississippi and let us spend some time with the softer side of Dr. Benton (Eriq La Salle).

This is a solid episode whose slow buildup of tension isn't even seen by viewers until the wallop-packing, heart-wrenching cliffhanger ending, which leaves two characters' lives in the balance as they helplessly watch each other suffer.

Sally Field shines as Abby's (Maura Tierney) unstable mother in this episode, but Benton's attempt and failure to save his nephew also hits hard in the best way possible - ER was at its strongest when it intertwined character-building, emotional impact, and clinical knowledge.

A true heartbreaker for fans, who watch Dr. Greene come to grips with his looming death and try to smooth his troubled relationship with his daughter (a setup that would land with full emotion in the show's final episode). Death, never mind a beloved character's death, has rarely been handled so eloquently.

The end of an era on the show, as the very next episode 'Kisangani' sets Carter (Noah Wyle) up working with Doctors Without Borders alongside Kovac (Goran Visnjic) in the Congo. The split-screen works to parallel the stories instead of feeling gimmicky, doubling the tension that must happen in every real ER with multiple patients' lives on the line — it's a treat to get the full sense of it on primetime television.

While we have to acknowledge "Freefall" for its completely bananas dispatching of Dr. Romano (Paul McCrane), this episode seems to be asking the question of where the show was headed — answered with the arrival of future fan favorite and show staple Neela (Parminder Nagra).

ERs aren't exactly the place for stable, ongoing doctor/patient relationships, but this episode gives a larger sense of the hospital as a community at the center of a city. Throwing all the way back to Season 2's "True Lies," Ruby (Red Buttons) returns and still wants nothing to do with Carter. It's a fascinating measure of just how far the show's come.

Though there were plenty of subplots that happened outside the hospital, they were more distracting than compelling. This is a solid night-in-the-ER episode with some character twists and a solid running gag resulting in Jerry (Abraham Benrubi) getting a jolt.

In the show's weakest season, this episode rises to the top by not being the worst. Even the major heartbreak for Abby and Kovac doesn't have the emotional impact of past episodes, and Sam's (Linda Cardellini) wrap-up is buried in the background. What brings it to the top of the heap is the reappearance of Sally Field as Abby's mother Maggie.

Despite having to deal with the cheesy cliffhanger hangover from Season 13, the penultimate season starts strong (maybe too strong, since this one outshines the rest of the season) with a major casualty episode affecting a number of newer characters we'd come to love, particularly Neela. The bomber melodrama comes up, but doesn't outshine the humanity of the rest.

There's no way any other episode this season could've topped the series capper, which has one of the sweetest codas possible for a show about trauma and loss.

Of course, there's plenty of latitude when it comes to choosing which ER episodes are "best," but that's all the more reason to keep rewatching.