Castrato
The popularity of castrato singers died out in the 19th century. By the mid-19th century they were no opera castrati left, although a few castrati still sang in church choirs. The last one, a man called Alessandro Moreschi, died in 1922 aged 64. There is a recording of his voice made in 1902 which can be heard online, but he may not have been a good singer and he was old when he made the recording, so we cannot judge whether the castrato voice was beautiful by that recording.