Question: 1. They are some places I never knew existed but they do and even look nice
2. They are some places I never knew they existed but do and even look nice
3. They are some places I never knew existed but do and even look nice

Which sentence sounds more natural? Never know what to choose...

Thanks, in advance

Answer: 
I find 1) the most natural, but it would be even better with *they* repeated again before *even look nice*. 

3) is comprehensible, and I think it is even grammatical, but I find it odd, because by the time I get to *but*, I've forgotten which verb *do* is supposed to coordinate with. 

2) doesn't work.
Choice 3. Choice 1 sounds okay as well (in US-English), but not choice 2.