Firstly, 'How to get to Galata Tower?' isn't a question. It might be a title of paragraph or note telling you how to get there. But as a question, it is neither meaningful nor grammatical.
A correct question might be, for example 'How do I get to Galata Tower?'
Note that there is no 'a'. Names of places can take either a definite article (the) or no article at all.
'How do I get Galata Tower?' is wrong. If you are using 'get (to) ' in the sense of 'arrive at/reach' you have to use the preposition 'to' to indicate movement from one place to another. Without the word 'to', the verb 'get' has other meanings, such as 'receive' or 'obtain'. If you were a multi-millionaire and you wanted to buy the tower, you might say to your business advisor 'How do I get Galata Tower?' but that means something very different!
The only situations where you can use 'get' in the sense of 'reach' without 'to' is when you are using adverbs. Examples are : get here, get there, get home.
Otherwise, you always need 'to'. Get to London, get to work, get to the bank.
I hope that helps.