The Halos are these big weapons to destroy all life right?

Then why have they got mountains, trees, oceans, rivers and land on there surface?

......

The halos were a means of containing the Flood + an anti son-of-a-bitch machine

@sieanr

Then why build all the mountains and oceans etc if it were to just contain the flood?

@azzer

For sexual reproduction.

That still doesn't explain it sieanr. i've asked myself this question several times and came to the conslusion it's only becouse its nice.

Its eaiser if you thhink of it outside the context of the game. They put that crap on their so you could explore the halos, it makes the game more exciting...

no one have an answer for me? :(

I thought it had something to do with creating an atmosphere to intensify the beam o.o but maybe thats just me XD

Really, it's to make a more interesting game...but I thought Halo had a big backstory in books and everything...didn't they explain why somewhere? I only played through the Halo 1 campaign, so I dunno.