Thread: std::vector<string>

I have a general wondering about std::vector<string>.

If you declare something like this, I have set 1 million elements to this vector.
If I run this program just declare it like this without filling the elements with any strings.
Does this take up any RAM memory just because I have declared this number of elements or do I have to fill them up to take up RAM.
Then I do wonder how many MB is 1000000 (1 million elements) ?

Code:

std::vector<string> vec(1000000);