The comments on the video gives some background information:
The dawn blast, which police believe was carried out by leftist or anarchist guerrilla groups, also came a day before a planned visit to Athens by German Chancellor Angela Merkel.
An anonymous caller warned a newspaper about 45 minutes before the explosion just before 6 a.m., saying it contained about 70 kg (155 pounds) of explosives, a police official said on condition of anonymity.
A news website also received a warning call.
Witness Paris Tzanetis, who at work in a building close to the bomb site, said he came outside after hearing the blast.
"We heard the explosion, we came downstairs to see what was happening. The road was closed, police had gathered, it was closed on both sides of the street. The police were already here, they said there had been an explosion, they wouldn't let us go anywhere," he said, adding that the blast had been "very strong".
The bomb exploded in one of the busiest parts of central Athens, in an area that is lined with banks, shops and a mall.
Greeks arriving for work were faced with the sight of the burnt remains of a car in the middle of the street and expressed shock that something like this could occur in such a central street.
"I wonder how a bomb could go off in the most well-guarded area of Athens," said lawyer Christos Panagiotopoulos, who could not reach his office.
Makeshift bomb and arson attacks have escalated since Greece adopted unpopular austerity measures in exchange for multi-billion euro bailouts by the European Union and International Monetary Fund from 2010.
Athens, which is seeking to send a strong political and economic signal that it is finally exiting its debt crisis, is expected to tap bond markets later on Thursday.
But public anger remains high after six years of recession that has sent unemployment to record highs of nearly 28 percent, eroded living standards and shut down thousands of businesses.