Venice tested 78 inflatable flood barriers in an attempt to protect the city from high tides.
The project has been subject to several delays and was supposed to start in 2011. Now officials hope to have the barriers working by 2021 to prevent floods in the Italian city.
Italian Prime Minister Giuseppe Conte inflated the bright yellow barriers at a ceremony on Friday by pressing a button to activate compressors to pump air into them.
Venice suffered its worst flooding in more than 50 years in November 2019. City officials estimated flood damage to be roughly one billion euros.
The barriers are designed to protect Venice from tides as high as three metres. In the November flood, the tide surged to 1.87 metres.
The project started in 2003 but has been delayed due to corruption. The project has cost nearly six billion euros.
It's named the "Moses" project, after the Biblical figure who parted the Red Sea, and as an acronym for the modules according to AP.
Environmentalists, nonetheless, are concerned that the project could damage the lagoon's fragile ecology. Some waved protest banners on Friday.