I love these a capella versions of songs with great singers such as Freddie Mercury.

Mercury is still considered one of the best voices in rock music even over 26 years after his death. When you hear a Queen song, you know what band you're listening to just from his unique voice.

When you're able to strip down all of the music, and leave just his voice, you really get a clear picture of WHY he is considered one of, if not THE best voices in rock.

It's actually been studied by science as to why his voice is so unforgettable.

“Usually, you can sing a straight tone, but opera singers try to modulate the fundamental frequencies,” he told NPR. “So they make the tone, if you like, a bit more vibrant. Typically, an opera singer's vibrato has this frequency of about 5.5-6 Hz. Freddie Mercury's is higher, and it's also more irregular, and that kind of creates a very typical vocal fingerprint.”

And there are quite a few a capella videos from Queen. They're all great!