Thousands of students, teachers, parents and workers have demonstrated across Greece, demanding more funding for public education and measures to ease rising living and study costs, public broadcaster ERT reported.
Around 10,000 people joined a march in Athens on Wednesday, while an estimated 2,000 to 2,500 demonstrated in Thessaloniki and more than 3,000 took to the streets in Patras, according to ERT.
Rallies were also held in Larissa and other cities.
Protesters demanded that thousands of teaching vacancies be filled, substitute teachers receive permanent positions, class sizes be reduced and school buildings be made safer.
University students called for lower rents, increased housing allowances, more places in student dormitories and the repeal of legislation on student expulsions.
Primary school teachers held a 24-hour strike, while secondary school teachers staged a three-hour work stoppage. Public sector workers and other unions also joined the demonstrations.
In Athens, protesters gathered at the Propylaea before marching to Syntagma Square and returning to their starting point.
The main march ended peacefully shortly before 2 pm local time, ERT reported.
However, disturbances were reported in the nearby Omonia area, including stone-throwing and damage to electric scooters.
Police used stun grenades, while Molotov cocktails were reportedly thrown.
According to the report, police detained 21 people during preventative checks in Athens, where more than 3,000 officers were deployed across central areas, including shopping streets.
In Thessaloniki, police took 10 people in for questioning.
The march there ended without further incidents after some participants lit flares outside the US Consulate.
Students occupied 18 schools in Thessaloniki, bringing the total number of occupied schools across Central Macedonia to 30.
The demonstration in Patras ended peacefully, while participants at the Larissa rally expressed solidarity with protesters in France.
"From Greece to France, we are fighting for free public education," read a slogan at the rally.
