The world's largest tidal turbine has been installed at the European Marine Energy Centre in Orkney.
The SR2000 is more than 200ft long, weighs more than 500 tonnes and is expected to generate enough electricity to power about 1000 homes a year.
It was towed out to sea from Haston Pier in Kirkwall and secured to its moorings at the EMEC on Wednesday.
Trials are expected to begin on the two megawatt turbine later this month after it is connected to the grid.
Andrew Scott, chief executive of developers ScotRenewables, said: "This is a tremendous achievement for the company and, I'd venture, for the tidal sector.
"It has only been possible through the determination, vision and ingenuity of a small, but highly determined team that has worked relentlessly to get to this exciting milestone."
Lang Banks, director of environmental charity WWF Scotland, said: "If Scotland is to continue to lead the world in pollution-free wave and tidal power then trials like those undertaken in Orkney are important.
"Along with action to improve energy efficiency, marine renewables have the potential to play a role in powering our homes and businesses in the future.
"If we are to secure such a future it's important that the Scottish Government's forthcoming energy strategy sets an ambition to secure at least half of all our energy needs from renewables by 2030.
"Doing so would ensure Scotland maximises the benefits from a transition to a zero-carbon economy."