Omg how is this done

very neat effect – mouse over the map (in computer I mean… they also have sthg neat on mobile, but am on a slow connection and I can’t really appreciate it… the effect on computer doesn’t seem to depend on being online…)

See:
https://www.w3schools.com/howto/howto_js_image_magnifier_glass.asp

EDIT:
To get similar shading near the edge of the magnifying glass use something like:
box-shadow:0px 0px 20px gray inset;

I think the actual one used on that site is MagicZoomPlus which you have to pay for but as shown above by @Archibald there are some free versions about that do similar effects. It’s a matter of finding the one that suits best or indeed writing/adapting your own. :slight_smile: