To simplify the expression \((x^6)^5\) using the Power Rule of Exponents, which states that \((a^m)^n = a^{m \cdot n}\), we can apply this rule as follows:
\[ (x^6)^5 = x^{6 \cdot 5} \]
Now, calculate the exponent:
\[ 6 \cdot 5 = 30 \]
Thus, we have:
\[ (x^6)^5 = x^{30} \]
So, the simplified expression is:
\[ \boxed{x^{30}} \]