There are many web sites which show current fires in Europe, but if you want to embed them in an HA iframe, the dreaded "refused to connect" will often appear. This is because the website implements "X-Frame-Options: SAMEORIGIN - Content-Security-Policy: frame-ancestors 'self'", essentially designed to stop people embedding the website in a scam website.
But, I found one that does not have such restrictions https://www.firemap.live/. Just zoom into the area that interests you and click Share Map. My yaml looks like.....
type: iframe
url: FireMap: Track Wildfires in Real-Time with Data from NASA & Local Authorities
grid_options:
columns: full
rows: 13
Hope this helps someone.