What is the result of $2^{{2}^{{2}^{{2}^{0}}}}$? What is the result of $2^{{2}^{{2}^{{2}^{0}}}}$?

It seems simple but I don't understand it.

Edit: Whoever is down-voting, please leave a comment as to why...
$$2^0=1$$
$$2^{2^0}=2^1=2$$
$$2^{2^{2^0}}=2^2=4$$
$$2^{2^{2^{2^0}}}=2^4=16$$
$2^{2^{2^{2^0}}} =2^4 =16$. Just gave the answer.