Police in Vienna shut off the B14 road into the city and stopped a train carrying hundreds of commuters after the 250kg bomb was uncovered in a building site.
The aircraft bomb was found early on Monday morning in the village of Kahlenberg just north of the city, leading to a closure of road in both directions and stranding thousands of commuters.
The bomb - which was found two-and-a-half metres underground - was moved out by authorities and traffic returned to normal around 9.30am.
The bomb is believed to be a relic from World War Two and was possibly made in America. It is quite common for bombs from this era to be found around Vienna.
In a separate incident involving a bomb, a 23-year-old “hobby bomb-maker” was released from custody yesterday after the discovery of three pipe bombs in his possession.
The first two pipe bombs were discovered in a hotel room of a 23-year-old and a 17-year-old in Vienna last week. The 23-year-old - who worked as a carpenter - had reportedly carried the two bombs in his backpack from his home in Carinthia to a construction job in Vienna.
Following the discovery, police took the two men into custody and searched their homes and the older man's workshop in the Völkermarkt district of Carinthia. In the latter they found a third pipe bomb, and nearby other spare parts for making bombs.
Although some media have speculated that the two have connections to right-wing extremism, police said last week that a terrorist or extremist connection could be “definitely” ruled out and the two men simply wanted to try and build a bomb for fun.
“They wanted to see ‘could we build a bomb and then also explode it'. And they wanted to see how big the explosion is and witness the detonation,” police spokesperson Thomas Keiblinger told Radio Wien.
The head of Carinthia's office for constitution protect and terrorism fighting (LVT) Helmut Mayer also confirmed that the older of the two men was a “hobby bomber” and the younger - a work colleague - was “a follower”.
The carpenter had told investigators that he built several of these “Easter firecrackers” that he then set off in front of his friend in a field near his home in the province, where lively Easter celebrations are particularly popular.
Prosecutors had requested that the 23-year-old be detained until a trial but on Sunday a court in Vienna ruled that he could go free until he later appears in court.