Greece's state broadcaster ERT went back on air on Thursday, two years after being closed down under austerity measures.
The radio and television channels shut in June 2013 after the then-government called it "a haven of waste".
The left-wing Syriza party made the reinstatement of ERT a key pledge in January's election, which it won.
The party said all of the more than 2,600 staff made redundant in 2013 have been offered jobs by the station.
"It's a special day for all Greeks, for those who love Greece and for those who love freedom of information," presenter Nikos Aggelidis said at the start of the first show on Thursday.
"We're nervous. We're very touched."
His co-host Vasiliki Haina said: "It's a special day for us, a difficult day."
ERT's television channel went off air in the middle of a programme in 2013, and viewers saw only a black screen. There had been no warning of the channel coming to an end.
The decision to end ERT, which cost €300m (£219m, $337m) to run, led to protests on Greek streets.
But some said the network was plagued by cronyism and had appeared immune from cuts and reform.
Analysis from BBC Monitoring's Stella Athanasoulia
The relaunch of ERT's radio and tv broadcasts was not devoid of symbolism. Early this morning, with the national anthem playing in the background, the ERT logo was displayed prominently once again alongside the Greek flag.
There then followed a video showing every ERT logo since its creation, right up to the black screen marking its closure in June 2013.
ERT's first programme today featured a series of back-to-back interviews with high-profile figures from the ruling Syriza party, including the speaker of parliament.
A concert by ERT's musical ensembles outside the station's headquarters is to be broadcast live on TV and radio this evening, followed by "The lost signal of democracy" - a documentary looking back at events since the previous government decided to close ERT.
Journalists have mixed feelings about ERT's comeback. The Greek Federation of Editor Unions (POESY) has supported it but the Federation of Unions of TV and Radio Employees (POSPERT) has cast doubt on the transparency of the relaunch procedures and has called for a gathering outside ERT's headquarters tonight.
While ERT continued to broadcast on the internet, a smaller-scale replacement, Nerit, was introduced in May last year.
Nerit enjoyed moderate success despite a smaller staff, and secured Champions League football coverage and rights to broadcast the Eurovision song contest.
Nerit's television operation merged with ERT on Thursday morning.
The letters N and I were removed from the sign on Nerit's building to spell ERT earlier this week.
ERT will be funded by a €3 surcharge added to electricity bills - less than the surcharge before it went off air.
Greece's government, which is fighting to secure loans to help stabilise the country's finances, called the reinstatement of ERT "a victory for democracy".