Weird light coming from underneath meshes

So I have this weird light coming from underneath my meshes.
I built everything and it’s still there and when I delete all my spotlights etc it turns dark (of course) but the bottoms of all these meshes are still lit up for some reason. Does anyone know what might be causing this?
This should make it clear:

My guess is that your meshes are going through the landscape and are receiving illumination from the sun

I got a huge plane with a highly reflective water material on it underneath my landscape and it might be reflecting light back up through my landscape mesh on the bottom of the meshes.