Strauss & Mozart in the Kursalon.

The "Kursalon" built in 1865 - 1867 must surely be counted as one of the most beautiful buildings in Vienna.
I went there yesterday evening to hear a concert of the two icons of Austrian Music:
Mozart and Strauss.
A small orchestra, consisting of 9 superb musicians played the old standards. Featured were two ballet soloists and two (male/female) Opera singers who rounded out an enjoyable evening.

One small caveat though: After you have heard this kind of assemble playing those same numbers, everything sounds a little hackneyed and one wishes for something new.

Two ballet dancers do the "Vienna Waltz" to Johann Strauss'

"Blue Danube Waltz"