Vocarska is an unexceptional street of the kind you might find in good neighbourhoods of many European capital cities. The road is in Zagreb’s Medvescak district, an easy walk east from the city centre. It is home to some pleasant villas, several university buildings, a Croatian Catholic radio station, the American International School, the Ukrainian embassy and the planet Jupiter. Yes, you will find Jupiter just beside the pavement near 71 Vocarska.

Kids on the way to school might pause and wonder why a small silver sphere lies by the pavement. And why does the adjacent sign suggest that this is the planet Jupiter?