The annual event involved pupils taking part in a particular activity for 12 hours to raise funds for charity.
Each year, the marathon was held in aid of a different cause – in 1999 it was the British Heart Foundation.
That year, 250 pupils signed up for the event – a record number.
1. Boston Grammar School 12-hour marathon, 1999
On the ball for 12 hours of fundraising in 1999, a group of football fans from Boston Grammar School. Photo: Boston Standard
2. Boston Grammar School 12-hour marathon, 1999
Table-tennis enthusiasts at Boston Grammar School getting ready for a marathon session for charity. Photo: Boston Standard
3. Boston Grammar School 12-hour marathon, 1999
Chris Flannery, Robin Long, Robert Simpson, Thomas Smalley and Ian Standen from Boston Grammar School making models. Photo: Boston Standard
4. Boston Grammar School 12-hour marathon, 1999
Another one of the day's activities under way. Photo: Boston Standard
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