Edinburgh's world-renowned festivals are kicking off their three-week run in the Scottish capital, 70 years after their first outing in 1947.
The Edinburgh International Festival will open with Bloom, a spectacular sound and light show that will transform the city's St Andrew Square.
Meanwhile, the Fringe will feature a massive 3,398 shows in 300 venues.
A number of venues have said they will be carrying out bag checks for the first time as security is tightened.
Security barriers have also been installed to stop terrorists driving vehicles into pedestrians.
Big names on the Fringe include Scots comedian Craig Ferguson, who last performed at the festival 23 years ago.
Ferguson, 55, who went on to find fame as a chat show host in the US, told BBC Scotland: "I started at the Edinburgh Festival in 1986. I did an act called Bing Hitler upstairs at the Cafe Royal and it was a spectacular introduction to the business I still work in. I loved it.
"In 1994, I decided to go to America for two weeks and that's me just getting back after 23 years."
Ferguson will not being doing stand-up at the Fringe but the former Late Late Show host will be presenting his radio show.
"I don't make plans and it tends to work out for me," he said.
Among those making their Fringe debut is former Scottish First Minister Alex Salmond who will appear in 15 shows, which have already sold out.
The former SNP leader's show is described as a "festival of fun, friends and freedom" and a chance to find out what he "really thinks".
Labour leader Jeremy Corbyn is also set to appear in a one-off show at the end of August.
Edinburgh festival - potted history
The Edinburgh International Festival was set up two years after the end of World War Two as a new "platform for the flowering of the human spirit".
It was the idea of Rudolph Bing, an Austrian Jew who had fled the Nazis.
The International Festival with its diet of the world's best classical music, opera and theatre was - and still is - by invitation only.
Eight drama companies turned up uninvited in 1947 and performed on the fringe of the official festival.
Over the years the Fringe has grown to dwarf its high-culture counterpart.
More seasoned Fringe performers who are returning this year include comedians Ruby Wax, Sue Perkins, Sean Hughes and Alexi Sayle.
Trainspotting author Irvine Welsh is behind two shows that feature.
One of the shows, Creatives, is described as a darkly comic "pop-opera" examining the contemporary music industry.
As usual global politics will feature prominently in the Fringe shows, with productions about Donald Trump and Brexit among the line-up.
This year's international festival will feature nine operas including Verdi's Macbeth, which was performed at the first festival.
The festival begins with a free open air event, called Bloom, which continues the theme of flowering culture.
Organisers say people will be able to immerse themselves in a "digital constellation" during the two-hour event.