What’s a great song? It’s not necessarily something we can define, but we know a great song when we hear one. Great songs never get old. They endure throughout the years, enjoyed by listeners new and old — despite changing music tastes and trends.

The best songs become musical touchstones, embedded so deeply in our culture that it’s impossible to imagine a world without them. Not only did they prove hugely successful upon release — frequently shooting up the music charts — but they’ve also permeated society in the years since, featuring prominently on radio, in movies, and being covered by other artists.

24/7 Tempo has determined the 50 absolute best songs of all time based on numerous metrics, including Billboard performance, number of cover versions, and recognition among music fans and professional critics.

While all musical genres were considered for this list, rock and roll accounts for many of those listed. Rock music has proved tremendously popular since its inception. Furthermore, artists such as The Beatles, The Rolling Stones, and The Beach Boys helped push the boundaries of not just of rock and roll, but popular music, too. These bands are now considered to be among the best ever. These are the most popular rock bands of all time.

The 1960s seem to have been the peak of creativity in popular music. While the list features songs from every decade from the 1950s through the 2000s, more than half charted on Billboard’s Hot 100 popular music chart in the 1960s. The work of artists active during that decade is held in higher esteem than most other artists active in other decades. These are the most famous musicians born the year you were born.

Regardless of release date, these are the songs that have both commercial as well as critical appeal, captivating music fans, reviewers, and performers.

Click here to see the 50 absolute best songs in history.

To determine the 50 best songs in history, 24/7 Tempo generated an index based on rankings on the Billboard Hot 100 chart and performance on Ranker.com’s user-generated list of the best songs. The number of times the song has been covered by other artists, as well as whether or not it was included — and, if so, its rank — on “Rolling Stone’s 500 Greatest Songs of All Time” list were also considered.

To be considered for inclusion, a song must have both charted on the Billboard Hot 100 and be included on Ranker.com’s list of the best songs of all time. How well a song performed on the Billboard Hot 100 was determined by awarding points based on the number of weeks it charted and its rank for each week. Data on the estimated number of times a song has been covered was provided by SecondHandSongs. Performers were not permitted to have more than three songs included on the list so as to increase variety. Songs performed under multiple names were not counted for the same tally, however. For instance “The Beatles” and “John Lennon” were counted as separate artists. Finally, editorial discretion was used to include songs that, in rare cases, performed exceptionally well in certain metrics but not others.