  The OPERA experiment was designed to observe ${\nu_{\mu}}$ ${\rightarrow}$
${\nu_{\tau}}$ oscillations through ${\nu_{\tau}}$ appearance at a baseline of
730 km in the CNGS beam. Newly developed emulsion analysis technology allows to
measure ${\nu_e}$, ${\nu_{\mu}}$ and ${\nu_{\tau}}$ interactions with the
largest emulsion detector ever made. OPERA has detected five ${\nu_{\tau}}$
candidates, allowing to reject the background-only hypothesis at 5.1
${\sigma}$. The parameters for standard and non-standard oscillations are
measured and constrained.
