A lighting test was carried out on the Kelpies in Falkirk, central Scotland, before they play a key role in a series of events beginning next week.
A night-time arts event, described as the international launch of the Kelpies, will take place at the equine sculptures on April 17 and 18. Artist Andy Scott's 300-tonne, 98ft (30m) sculptures of horses' heads will be "brought to life" with a light, sound and flame performance by a pyrotechnic company.
The spectacle, which organisers hope will draw a crowd of thousands, will also mark the launch of this year's John Muir Festival.
Members of the public will then get a chance to tour the structures for the first time from Monday April 21.
The completion of the £5 million Kelpies, which are based on real life Clydesdale horses called Duke and Barron, marked a significant stage in the £43 million Helix project, which is transforming 865 acres (350 hectares) of land between Falkirk and Grangemouth.
The redevelopment is expected to attract an additional 350,000 visitors and add £1.5 million in annual tourism spend to the area, according to those behind the project.
VisitScotland chairman Mike Cantlay said: "The John Muir Festival, which will launch with the official opening of this fantastic new landmark, will form a key part of our Homecoming Scotland celebrations, honouring an iconic, brilliant man from Scotland's past as well as celebrating our country's breathtaking landscapes.
"The Helix is set to be a major attraction in Scotland, bringing thousands of people - and real economic benefit - to the local community.
"The impressive Kelpies also offer a fitting tribute to Scotland's strong industrial past, as well as celebrating the myth and folklore that has encapsulated the imagination of visitors to Scotland for centuries."