Two dimensional arrays and slices are useful for many situations. When creating an array in the Go programming language it is automatically initialized to the empty state, which is usually a 0. Arrays cannot be expanded. Arrays live in the stack and take up space in the compiled executable. Arrays are also passed by copy whereas slices pass pointers. Slices require a little more initialization at first but are more versatile. You can grab subsets of the arrays if needed, access elements directly, or expand the slices. Slices are thin wrappers around arrays and hold pointers to the array. They are initialized during run time and live in the heap.