What is the difference between vector

vector<vector<int> > vect; // used for 2D array
vector<int> vect[N]; // used for Graph

How do I visualize it? The first one is 2D array which is something like below

{ { 1, 2, 3 }, 
{ 4, 5, 6 }, 
{ 7, 8, 9 } }

Isn't vector vect[N]; also the same?