Multidimensional Arrays

Hello!
I’t trying to create a multidimensional array of the following kind:

let’s say we have a list of cities:
Rome, Paris, London
and a list of neighborhoods for each(i.e: rn1,rn2,…for Rome)
How can I create one array that holds all that information like:

var travel = new Array()
//and the travel array hold information like:
Rome(rn1,rn2,rn3),Paris(pn1,pn2),London(ln1,ln2,ln3,ln4)

so later I could access travel[0] = Rome, travel[1] = Paris
and…
travel[0][0] = rn1
travel[1][1] = pn2

or something like it…
thanks!
:pac: