In the sphere were holes that started glowing white at the end after one of the main characters get inside it.
I think two groups fight to get it. One may be some Victoria-era-dressed British explorers with locals that worshipped it.
I think this could be a Secret of the Sahara 1988 Italian TV miniseries, featuring Michael York, Ben Kingsley, Andie MacDowell, about
the quest of archaeologist Desmond Jordan to discover the location of the legendary Talking Mountain of the Sahara desert, and find the secret that it hides
Trailer(?) where spherical object partially submerged in the pool is visible, also at different time in the trailer there is glowing orb present.
From what I recall seen the series about 30 years ago, it was about ancient crashed alien spacecraft, a particular Sahara people tribe being the descendants of the aliens, protecting it.
There seems to be complete series on Youtube (found the Polish dub version), but due to possible copyright issues, I won't post the link here.