The eighth wonder of the world is "compound interest" (or "compound growth" in this case). eg - You add £10k, get 8%, you now have £10,800. Next year you add another £10k, meaning you get 8% on £20,800. A total of £22,464. Einstein allegedly said “Compound interest is the eighth wonder of the world. He who understands it, earns it; he who doesn't, pays it.”