It is impossible to establish scientifically who is the best singer ever. It is possible, however, to establish who the singers with the greatest vocal range ever are.
This ranking was compiled by the website concerthotels.com, which checked which was the lowest and highest note singers hit when recording their songs in the studio.
The ranking will surprise you: singers such as Beyoncé (22nd) and Michael Jackson (26th) are not included in the top 20.
However, the list does not take into account the vocal performance within the same song (i.e. the highest and lowest note reached in a single song), but rather the highest and lowest notes reached in the artists' entire repertoire.