A few old webpages that still have their old designs.
+25 years old:
Britney Spears as a semiconductor physics expert: https://britneyspears.ac/lasers.htm
https://www.pbs.org/transistor/ Story of the transistor. (almost 30 years old?)
https://vetusware.com/ tons of abandoned software, I used to visit this site back in early 2000s. It hasn't changed a bit.
This doesn't have https but it is safe to visit, I loved its gallery http://www.fractalzone.be/
Smallest web page! https://www.guimp.com/
+20 years old:
https://particleadventure.org/ educational particle physics website.
https://www.bogozone.net/freecow.html weirdest comic I found back then. Love it.
+15 years old:
http://brawlinthefamily.keenspot.com/archive/ hilarious comic based on nintendo characters. Doesn't have https but it is safe to visit.
https://scaleofuniverse.com/ science web about the scale of the universe!