Spanish unions are holding a general 24-hour strike to protest against labor reforms, austerity cuts, and soaring unemployment.
Rail, bus, and air services were all affected, and some factories came to a standstill.
There were reports of isolated violent incidents as pickets tried to block the departure of buses in some places as well as the entrances to some wholesale markets.
Cars clogged the roads in the morning rush-hour in central Madrid.
Organizers said that participation in the strike was "massive," authorities downplayed those claims.
It is the first strike since Prime Minister Mariano Rajoy's conservative government took office.
Rajoy was sworn in 100 days ago, pledging to cut Spain's 23 percent unemployment rate and steady its shaky finances.
Based on reporting by AP, AFP, and Reuters