"Expedition" or "Exploration"?

[ngoc_lan]

I've checked in my bilingual dictionary (of course English - Vietnamese dictionary)
that these 2 words have the same meaning. So I'm confused whether which word
is correct for this sentence:
The ________ to the South Pole had to be delayed because of dangerous
weather conditions. ("Expedition" or "Exploration"?)

I hope to receive answers from you. Thank you.

[ngoc_lan]

Thanks a lot!