'the' + place names: eg. 'the Yokohama plant' vs 'Yokohama plant'

[Xxxholic]

I've been discussing this with my colleagues:
When is it correct/incorrect to use the article 'the' before a place name?

'I went out to the Yokohama plant last week.'

'I went out to Yokohama Plant last week.'

'The Victoria Falls are so beautiful.'

'Victoria Falls are so beautiful.'

[Hyder12]

From my limited knowledgement

I think if the place is known there is no need for article"the">>....

I hope I reach my point to you.

[Xxxholic]

Thanks for your answer, but I was hoping for a more grammatical explanation.