They landed on planet...

Unfortunately, After Worlds Collide, which George Pal originally planned, never got made. Try reading the original book sequel to discover what they find on that planet. Pretty zippity stuff as I recall from my read 50 odd years ago.

and there were structures on it -- 2 pyramids in the distance and some sort of building up close on the left side. They didn't even act surprised. What if the natives didn't like them?