For its time, a running time of nearly six minutes for a single was frankly unusual. Radio stations preferred tracks of three to four minutes, yet the song broke through regardless and became a massive hit.

The structure is essentially a sequence of distinct worlds strung together: a quiet intro, a piano-led ballad, a theatrical operatic section, a hard rock eruption, and then a restrained closing passage. No returning chorus, no anchor in the conventional sense.

Those layered vocal parts in the operatic section are the result of the band members recording their voices over and over again and stacking them on top of one another. With analogue recording equipment, that took dozens of hours of studio work at the time.

Decades later, the song found a whole new audience through films and new generations of listeners. It continues to appear in music lists, and that is hardly surprising: there are very few songs put together with such singular vision that have also connected so broadly.