The International Space Station is passing over Bucharest every night as of yesterday, August 6 until August 22. If the sky is clear, ISS can appear as a very shinny flying object going smoothly.
According to NASA website, ISS can be observed for several minutes. It can be spotted tonight above Bucharest at 10:07 P.M for three minutes. Tomorrow, Wed Aug 8, ISS can be seen at 9:16 PM for four minutes, while on Friday Aug 10, at 9:08 PM for three minutes.
NASA has launched a service through which people can be notified by email or SMS to find out few hours before that ISS will pass over their city.
All sightings will occur within a few hours before or after sunrise or sunset. This is the optimum viewing period as the sun reflects off the space station and contrasts against the darker sky.
More details here.