In this fascinating study by Jovana Bila Dubaić et al. of over 1300 nests and swarms over a 7 year period in Belgrade we see that free-living bees are thriving in the Urban setting. From the paper:
"Herewith, we present another case of unmanaged, free-living population of honey bees in SE Europe, a rare case of feral bees inhabiting a large and highly populated urban area: Belgrade, the capital of Serbia. We compiled a massive data-set derived from opportunistic citizen science (>1300 records) during the 2011–2017 period and investigated whether these honey bee colonies and the high incidence of swarms could be a result of a stable, self-sustaining feral population (i.e., not of regular inflow of swarms escaping from local managed apiaries), and discussed various explanations for its existence." "Overall, molecular genetic analysis suggests the existence of a strong and genetically diverse population of feral honey bees in Belgrade. Hypothetically, this urban population of free-living honey bees may have existed in continuum from the period before the introduction of Varroa mite. Greater genetic diversity could have contributed to natural selection for improved tolerance against parasites and pathogens, and hence their capability for successful survival despite these pressures."
There are many interesting observations, and so we recommend reading the full paper.