The first of May (Protomaia) is a national holiday (Labour Day) in Greece.
I don't think that there is anything to do with the labour, but there is a custom to make a circle of flowers like this below.
I feel guilty to collect wild flowers, so I collect flowers with my camera. Most of them are from Hymittos Mountain.
It was a very fine day and there were people everywhere. Especially the traffic of Kaissariani side of Hymittos was dramatic, partly due to the people who dare to park the cars where they are supposed not to. Lesson learnt.