A laser show has been staged to celebrate the inauguration of London's Shard skyscraper.
Earlier, the Duke of York and the Qatari prime minister attended a ceremony to mark the unveiling of the 1,016ft (310m) structure, which has been funded by the Qatar National Bank.
At about 22:15 BST a light show began firing beams from the summit to London landmarks including the BT Tower.
The spectacle could be seen across the city.
During Thursday afternoon's inauguration of the building, which is yards from the banks of the River Thames in Southwark, Prince Andrew said the building was a "huge new boost".
He added: "I'm sure that we would all be extremely glad if this could be repeated in a number of other areas across the UK."
The Shard is joint-owned by the state of Qatar, and the country's prime minister Hamad Bin Jassim Bin Jabr Al-Thani also attended the ceremony.
However there was dismay from some Londoners about the cost of a visit to the Shard, as it was revealed it will cost nearly £90 for a family of four to ascend to the viewing platform.
Tickets to the platform - which opens in February - will cost £24.95 for an adult and £18.95 for a child.
By comparison, an adult ticket to the top of the Eiffel Tower in Paris is currently priced at 14 euros - just over £11.
Russell Gray, of the Bermondsey Village Action Group, said: "It does sound pretty exorbitant.
"I don't think many local people will be going up to the viewing platform at that price."
He continued: "We have this massive pyramid slapped down here as a monument to the munificence of the Emirate of Qatar.
"Yet the price is yet another of the many examples of how the Shard is clearly at odds with the community in which it's defiantly planted itself."
But the PR firm representing the project insisted it was competitively priced compared to other major London attractions.
A spokesman also pointed out that the "visitor experience" would include such attractions as "kaleidoscopic lifts".
Sheikh Abdullah Bin Saoud Al Thani, governor of Qatar Central Bank, which joint-owns the tower, said: "The Shard is the newest London landmark and a beacon of the city of London's resilience and expansion, even during tough economic times.
"The light show will mark a key moment for the Shard, and one people around the world can enjoy."
The laser show will culminate in the illumination of the Shard itself, with the ceremony streamed on the internet.
Architect Renzo Piano said: "Up until now the building was ours. Now the building is yours.
"This building is not going to be a symbol of power."
Former London mayor Ken Livingstone told BBC Radio Four's Today programme: "It will define London and it's our equivalent to the Empire State building.
"It brought 10,000 jobs to one of the most run down and deprived areas of London but unlike a lot of the other tall buildings, Londoners will have access to this one."