Balloon floats through melbourne city

This was an amazing thing I saw early one morning from the kitchen window. Quite often we get balloons floating around in the early morning, usually they are on the other side of the apartment. this morning I noticed one solitary balloon on the city side floating towards the city. I grabbed the camera and snapped it as it actually floated between the city buildings (from left of picture to right). I can only assume that they were off course!