I'm pretty sure that Layers of London has been discussed before in this Forum, but the Washington Post had an article today that cited it along with some other useful links which I thought deserved a new mention. One of the links that accompanied the article described re-creating a cancelled trip due to the pandemic by using sources on YouTube. Not as good as being there, but still worthwhile.
Here is a link to the Post's article:
In London, looking backward to move forward