Through '''concurrent_vector''', every time an element is accessed/changed, a return of the index location is given. TBB promises that any time an element is pushed, it will always be in the same location, no matter if the size of the vector changes in memory. With a standard vector, when the size of the vector changes, the data is copied over. If any threads are currently traversing this vector when the size changes, any iterators may no longer be valid. This support also goes further for containers so that multiple threads can iterate through the container while another thread may be growing the container. An interesting catch though is that anything iterating may iterate over objects that are being constructed, ensuring construction and access remain synchronized.