In what may be the biggest protest against Uber, more than 30,000 cab and limo drivers across Europe are reportedly staging demonstrations against the on-demand car service, stating that the company's arrival will threaten their livelihood.

Traffic came to a standstill in London on Wednesday as black cabbies staged a widespread strike against the Uber taxi-hailing app. (Casey Capachi/The Washington Post)


The protests have caused traffic jams and standstills in London. Here's a look.

Right before the protests from London's black cabs, Uber introduces UberTaxi:


London police are going cab to cab:


Outside Parliament:


The Strand:


Trafalgar Square:


Congestion in Whitehall:


A view from above:


Reports filter in about the cabdrivers' protests backfiring: