Let $a,$ $b,$ $c$ be positive real numbers such that
\[\log_a b + \log_b c + \log_c a = 0.\]Find
\[(\log_a b)^3 + (\log_b c)^3 + (\log_c a)^3.\]
Let $x = \log_a b,$ $y = \log_b c,$ and $z = \log_c a.$  Then $x + y + z = 0,$ so
\[x^3 + y^3 + z^3 - 3xyz = (x + y + z)(x^2 + y^2 + z^2 - xy - xz - yz) = 0.\]Hence,
\[x^3 + y^3 + z^3 = 3xyz = 3 (\log_a b)(\log_b c)(\log_c a) = 3 \cdot \frac{\log b}{\log a} \cdot \frac{\log c}{\log b} \cdot \frac{\log a}{\log c} = \boxed{3}.\]