I coded the website with the help of:

W3schools tutorials
sadgrl.online resources
Brackets, a free open-source editor
Ayano's comment widget
Quiz template by dashweb

The visual elements are from the following sources:

Internet Archive on Flickr
British Library on Flick
jojo-ojoj on DeviantArt
Leichnam on DeviantArt
Amaruuk on Ko-fi
patricia m on Flickr
devoral on DeviantArt
DaydreamersDesigns on DeviantArt

The photos used in the quizzes were taken by:

Krysten Merriman on Pexels
Dids on Pexels
Stefan on Pexels
Yusuf Evli on Unsplash
mk. s on Unsplash