One big block with 2 smaller blocks aligned to it

\documentclass{beamer}
\usetheme{Berlin}

\begin{document}

\begin{frame}{My Frame}
    \begin{block}{Block}
        Foo Bar  Foo Bar  Foo Bar  Foo Bar  Foo Bar  Foo Bar  Foo Bar  Foo Bar 
    \end{block}

    \begin{columns}[totalwidth=1.02\textwidth]
        \begin{column}{.47\textwidth}
            \begin{exampleblock}{Block}
            Foo Bar
            \end{exampleblock}
        \end{column}
        \begin{column}{.47\textwidth}
            \begin{block}{Block}
              Foo Bar
            \end{block} 
        \end{column}
    \end{columns}

\end{frame}

\end{document}