Buried on the B-side in 1950. It won an Oscar. Cigarettes took him at 45.

Hollywood, March 11, 1950.
Nat King Cole entered a Capitol recording session and sang Mona Lisa, a film song written by Jay Livingston and Ray Evans.
Capitol did not treat his recording like the obvious centerpiece of a major hit.
It was issued on the reverse side of another single.
Early advertising reportedly concentrated on the other side and barely acknowledged the performance that would eventually define the record.
Then listeners began finding it for themselves.
YOUTUBE 1 — NAT KING COLE PERFORMANCE
Cole’s recording was built around a striking contradiction.
His voice was intimate and warm, but the woman in the lyric remained unreachable.
He was singing to the image of Leonardo da Vinci’s mysterious subject, asking whether the famous smile hid loneliness or heartbreak.
The performance did not require vocal drama.
Cole made uncertainty itself sound beautiful.
Radio response grew.
The neglected side of the record became the side people wanted.
Mona Lisa eventually spent five weeks at No. 1 on Billboard’s singles chart and became one of the biggest recordings of Cole’s career.
YOUTUBE 2 — NAT KING COLE AUDIO
There is an important distinction in the story.
The Academy Award did not go to Nat King Cole’s recording.
The composition itself, written for the film, won the Oscar for Best Original Song.
Cole’s version then became the performance that transformed the composition into a huge popular standard.
That distinction makes the rise of the record even more interesting.
It did not need a massive promotional campaign.
It did not need to begin on the favored side of the single.
Listeners heard Cole and made the decision themselves.
Fifteen years later, the story acquired a much darker ending.
YOUTUBE 3 — 1950 RECORDING
Cole had been a heavy cigarette smoker for years.
In late 1964, doctors discovered advanced lung cancer. He underwent treatment and eventually surgery to remove his left lung.
It was too late.
Nat King Cole died on February 15, 1965.
He was forty-five years old.
The contrast with the 1950 recording is painful.
The voice on Mona Lisa sounds effortless—smoky, controlled and almost impossibly calm.
That warmth became one of the qualities audiences loved most about him.
But behind the voice was a man living in an era when the dangers of constant cigarette smoking were still routinely ignored, minimized or misunderstood.
In 1950, Capitol placed the recording on the side it expected listeners to overlook.
Listeners turned the record over.
Fifteen years later, the man behind that voice was gone.
The neglected B-side survived him—and became immortal.
Four Dead Students, One Magazine, and a Song That Could Not Wait
The photographs did not allow Neil Young the comfort of distance. In May 1970, Life magazine brought the violence at Kent State University into American homes, including John Filo's harrowing image of 14-year-old Mary Ann Vecchio kneeling beside the body of student Jeffrey Miller. Young saw those pictures and responded with "Ohio," a song written not as historical reflection, but as an alarm sounded while the crisis was still unfolding.
On May 4, members of the Ohio National Guard fired into a crowd during a campus demonstration against the expansion of the Vietnam War into Cambodia. Allison Krause, Jeffrey Miller, Sandra Scheuer, and William Schroeder were killed; nine other people were wounded. Some of the victims had been protesting, while others were passing nearby. The photographs made the event impossible to reduce to an abstract argument about war or campus unrest.
From the Page to the Guitar
David Crosby later recalled giving Young the magazine and watching the images hit him hard. Young withdrew with his guitar and returned with a song. Whatever private process took place in those minutes, the finished work carried the speed of first response: blunt language, a narrow harmonic frame, and a central question that refused to offer comfort.

That immediacy distinguishes "Ohio" from songs written after public wounds have become history. Young did not build an elaborate narrative or explain the politics in detail. He compressed the shock into repeated phrases, accusatory images, and the grim counting of four deaths. His guitar sounds raw and unsettled, more like an exposed nerve than a polished statement.
Crosby, Stills, Nash & Young recorded the song on May 21, 1970, little more than two weeks after the shootings. Young and Stephen Stills supplied the electric-guitar tension, while bassist Calvin Samuels and drummer Johnny Barbata gave the track its heavy, marching momentum. The group's harmonies, normally associated with careful blend and control, feel strained by grief. Near the end, Crosby's anguished vocal cries push the performance beyond formal protest and toward something almost unbearable.
A Release That Could Not Follow the Schedule

CSNY already had music in the marketplace, including "Teach Your Children," when the group decided "Ohio" had to come out immediately. Rather than save it for a future album campaign, they pressed for a rush release. Atlantic issued it as a single in June 1970, backed with Stills' "Find the Cost of Freedom."
That decision mattered. Popular records usually moved through long cycles of planning, manufacturing, promotion, and radio programming. "Ohio" entered circulation while Kent State remained a living national argument. Its direct reference to President Richard Nixon made the single politically confrontational, but listeners did not need to share every conclusion to recognize its urgency. The record reached No. 14 on the Billboard Hot 100.
More than half a century later, "Ohio" still sounds unusually close to the event that created it. There is little sense of hindsight and no attempt to smooth the edges. Young saw photographs of young Americans lying on a college campus, wrote before the shock could settle, and recorded before outrage could become ceremony. Listen again, and the most striking quality is not polish but pressure: four musicians treating delay itself as a failure to respond.