[Tex/LaTex] Upper triangular matrix with big zero in lower triangular

Question

I can represent an upper trapezoidal matrix say as shown below. I would like to replace all those zeros with a single big zero that spans across the low triangle rows and columns, and maybe also add a delimiter along the diagonal that clearly shows it is an upper diagonal matrix. How can I do that?

\newcommand\x{\XSolid}
%\newcommand\x{\ding{53}}
\begin{equation}
  \left(
    \begin{array}{*5{c}}
    \x & \x & \x & \x & \x \\
     0 & \x & \x & \x & \x \\
     0 &  0 & \x & \x & \x \\
     0 &  0 &  0 & \x & \x \\
     0 &  0 &  0 &  0 & \x \\
  \end{array}\right)
\end{equation}

Separate question … why the \x command I define outputs # rather than the intended cross symbol? It outputs the same symbol # no matter if I use \XSolid or \ding{53}

UPDATE: taking the answer as input, I ended doing this:

\newcommand\x{\times}
\newcommand\bigzero{\makebox(0,0){\text{\huge0}}}
\newcommand*{\bord}{\multicolumn{1}{c|}{}}
\begin{equation}
  \left(
    \begin{array}{ccccc}
    \x    & \x       & \x    & \x    & \x \\ \cline{1-1}
    \bord & \x       & \x    & \x    & \x \\ \cline{2-2}
          & \bord    & \x    & \x    & \x \\ \cline{3-3}
          & \bigzero & \bord & \x    & \x \\ \cline{4-4}
          &          &       & \bord & \x \\ \cline{5-5}
  \end{array}\right)
\end{equation}

which produces this:

Answer 1

\documentclass[]{article}
\usepackage{mathtools}
\begin{document}

\[
    \left(
    \begin{array}{ccccc}
    1                                    \\
      & 1             &   & \text{\huge0}\\
      &               & 1                \\
      & \text{\huge0} &   & 1            \\
      &               &   &   & 1
    \end{array}
    \right)
\]  

\end{document}

or \makebox(0,0){\text{\huge0}} if you want to have the same line spacing.