Experimenting with the new coffee machine.

Espresso with a small serving of sparkling water (called Sidecar). This is not as common in the USA but fairly widespread in Europe. By my personal experience, most all cafes in Italy, Australia and Germany serve some sparkling water with a shot of espresso.

I believe the sparkling water is to clean your palate before having the espresso. Water is also often served with coffee in the Middle East. I assume the practice there is to keep dehydration at bay. Coffee is a fairly strong diuretic.