While the wedding takes center stage, the hospital remains in chaos due to a tragic car crash involving college students on their way to graduation.
: To promote the 100th episode, ABC created a real wedding website for Meredith and Derek that fans could actually visit and RSVP to. [S5E22] What a Difference a Day Makes
In , the Season 5, Episode 22 milestone titled " What a Difference a Day Makes " is a landmark 100th episode that originally aired on May 7, 2009. It is widely celebrated for its emotional depth, shifting from a planned grand wedding for Meredith and Derek to a poignant ceremony for Izzie Stevens and Alex Karev. The Unexpected Wedding While the wedding takes center stage, the hospital
: Despite the shift in plans, the wedding remains a fan favorite, featuring the original "MAGIC" interns (Meredith, Alex, George, Izzie, and Cristina) as the wedding party. It is widely celebrated for its emotional depth,
: As a wedding gift, Derek gives Meredith her first solo surgery—a successful colon surgery overseen by Richard Webber.
: Jeffrey Dean Morgan makes a final appearance as Denny Duquette, appearing as a hallucination to Izzie that Derek and Bailey eventually realize is a symptom of her worsening condition. Behind the Scenes Facts
: Alex delivers a powerful, spontaneous speech adapted from a valedictorian's graduation address, promising to be accountable to Izzie through any future challenges. Medical Drama and Character Growth