The Antonov An-24 is one versatile aircraft. That aircraft lead to the An-26, which then lead to the An-32. Heck, the Saudis gave the Ukrainian government money to design the An-132. Reasons were given for the latter, I am sure.
All of those just haul people or cargo, though. BORING! What if you needed to observe something? What if you needed airborne survey? What if you wanted to do better cartography? Enter the rarest An-24 variant: the An-30 — only 123 were ever made.
It’s distinct from all the other An-24s in the world because, well… just look at it. The glazed nose for the navigator really sticks out and illustrates the fact that this is a rare breed of Antonov. It does more than look cool, though.