2020 used to sound like a futuristic year, and now here we are. Ready to feel old?

The year 2000, which caused pandemonium all over because of Y2K, was a whole two decades ago. Since then, due to the advancement of all types of technology, both music production and consumption have changed drastically. Songs were made available on the internet as platforms such as Napster began to gain popularity. iPods started replacing Walkmans. Music went from being tangible to a computer file.

With these innovations came new sounds in the music itself. The late '90s introduced nu-metal, and some rock and metal artists began rapping. Linkin Park became one of the most popular bands of the 2000s when they released Hybrid Theory in the first year of the millennium. Disturbed introduced "Ooh-wa-ah-ah-ah" with The Sickness. Pantera put out their final studio effort before Dimebag Darrell was murdered.

Plenty of veteran acts released new music in 2000 as well, proving that age is truly just a number. AC/DC were still going at it with Stiff Upper Lip and Ronnie James Dio was still wailing on Dio's Magica. 

2000 was the start of a new era and the end of an old one all at the same time. But in case you forgot just how old you are and needed a reminder, here are 66 rock and metal albums you didn't realize were turning 20 this year... and are going to make you feel like you belong in a museum.

50 Most Game-Changing Hard Rock + Metal Albums of All Time