Hundreds on Sunday commemorated the 20th anniversary of the Lockerbie bombing in which terrorists blew up a US airliner over Scotland, killing 270 people.
Crash investigators inspect the nose section of the crashed Pan Am Flight 103 in 1988
Pan Am Flight 103 from London to New York exploded in the skies above the Scottish town of Lockerbie on December 21, 1988. All occupants, as well as 11 people from the town, were killed.
Memorial services were held on Sunday in Lockerbie, Heathrow -- from where the aircraft took off -- and the United States.
Relatives of the victims and government officials were among those marking the event. Scottish First Minister Alex Salmond and Britain's Scottish Secretary Jim Murphy addressed the gathering.
"This was the worst terrorist attack on the United Kingdom," Murphy said. His thoughts were with the families who had lost loved ones in the attack, he added.
Death from the sky
Religious services were set for 7 pm, the time the bomb tore through the Boeing 747 at an altitude of 10,000 meters.
The names of those who died in the bombing at a memorial in Arlington Cemetery in the US
All 259 people on board were killed and another 11 died on the ground as burning debris and fuel from the disintegrating airplane rained down from the sky.
The bodies of the dead were spread over a wide radius and some piece of the plane were found up to 130 kilometers (80 miles) from the final point of impact.
Investigators from Britain and the US carried out some 12,000 interrogations in 54 countries trying to piece together what had happened.
In 1991, Britain and the US charged two Libyan agents with responsibility although Libya refused to allow the two suspects to stand trial in Britain or the US. The UN Security Council ordered an air and arms embargo against Libya as well as a freeze on its financial assets abroad.
In 2001, former Libyan intelligence agent Abdel al-Megrahi was convicted of mass murder in a special Scottish court in the Netherlands. The other suspect, Al Amin Khalifa Fhimah, was acquitted.
Investigators found the clues pointed to Libya
The 56-year-old al-Megrahi, who denies having smuggled the bomb onboard the aircraft, is due to serve another 20 years in prison before being eligible for parole.
His is suffering from advance stage prostate cancer and has been trying to secure early release.
In 2002, al-Megrahi failed in his attempt to appeal against his conviction, but the case was referred for review and negotiations could start in the coming year.