Events to mark the anniversary in Lockerbie will include a wreath-laying at the Dryfesdale cemetery
By Giancarlo Rinaldi
South of Scotland reporter, BBC Scotland news website
In every life there are a handful of events which go beyond our ability to fully comprehend or believe.
For most people in south west Scotland, the Lockerbie disaster was one such occasion.
The scale of death and destruction which fell from the sky onto a quiet, rural town is still hard to take in.
Such atrocities tend to be the unwanted preserve of major cities around the world - not the agricultural heartland of Dumfries and Galloway.
Pan Am Flight 103 might have come crashing to earth almost anywhere along its route through the skies.
LOCKERBIE RESIDENTS KILLED BY PAN AM FLIGHT 103
Kathleen Flannigan, 41
Thomas Flannigan, 44
Joanne Flannigan, 10
Dora Henry, 56
Maurice Henry, 63
Mary Lancaster, 81
Jean Murray, 82
John Sommerville, 40
Rosaleen 'Rosalind' Somerville, 40
Paul Somerville, 13
Lyndsey Ann Sommerville, 10
The fact that it struck Lockerbie has given the place the kind of fame it would have happily lived without.
Prior to 21 December 1988 it was just another proud farming town near the border between Scotland and England.
It was best known, perhaps, for its ice rink and a railway station linking the region to Edinburgh.
Since the events of that night 20 years ago, it has become known worldwide as the place where a Pan Am jet plunged out of the sky killing a total of 270 people.
It is a notoriety which the Dumfries and Galloway town has slowly come to terms with over the two decades since the disaster which scarred it deeply.
Initially, the area was a scene of devastation and distress.
A total of 11 people lost their lives on the ground, with wreckage strewn widely through the town and beyond.
David Steel talks to the BBC about past dealings between ministers and Colonel Gadaffi over the Lockerbie suspects
However, due to the nature of the disaster, its effect quickly spread way beyond south west Scotland.
Passengers on Pan Am Flight 103 came from around the world.
As investigations continued, two Libyans went on trial for murder. One of them was convicted and the other was found not guilty.
The proceedings took place at a special Scottish court in the Netherlands.
It all seemed a long way removed from the town where the plane crashed.
A high profile appeal by the man convicted of the Lockerbie bombing has gathered little coverage in the local media and provokes little interest in the area.
Lockerbie became known worldwide after the events of 1988
Residents seem to have left the distant wheels of justice to run their course.
Little wonder, perhaps, that the theme of events in Lockerbie this Sunday is "low key" - in line with the wishes of the local community.
A number of "Places to Remember" will be open throughout the day, including the Dryfesdale Lodge Visitors' Centre, Lockerbie Town Hall and Tundergarth Church.
A commemorative wreath-laying will also take place at the Dryfesdale cemetery, and there will be services at Dryfesdale and Tundergarth Churches.
No doubt the eyes of the world - and a massive media presence - will be concentrated on the town again.
It is something which Lockerbie residents have come to accept.
Then, when the attention has faded, they will surely return to the process which has occupied the past 20 years - getting on with their lives.