Golf's most famous bunker, in front of the green at the Road Hole at St Andrews, helps make the 17th arguably the toughest par four in the sport and the scene of much drama over the years.
It was dubbed "the Sands of Nakajima" when, at the 1978 Open, Japanese golfer Tommy Nakajima took four shots to escape from it.
In the 2000 championship, then world no. 1 David Duval emulated him and his four sand shots effectively handed Tiger Woods his first Open.
But when the world's best golfers reassemble at St Andrews in 2015, the challenge will be even greater: the Road Hole Bunker is to be widened by half a metre to the right and the green recontoured so that more balls are likely to be gathered in.
The work is among a number of alterations by architect Martin Hawtree, who was commissioned by St Andrews Links Trust and the Royal and Ancient Club.
The first phase will be at the second, seventh, 11th and the Road Hole. The second phase will take place in winter 2013/14 with work on the third, fourth, sixth, ninth and 15th.
Peter Dawson, R&A chief executive said: "We have considered the challenge presented to the world's top golfers by each of the Open Championship venues and carried out a programme of improvements over the last 10 years.
"While some holes have been lengthened on the Old Course in recent years it has otherwise remained largely unaltered.
"The Championship Committee felt there was an opportunity to stiffen its defences in some places to ensure it remains as challenging as ever to the professionals.
"The proposals from Martin Hawtree should place more of a premium on accuracy and ball control while retaining the spirit and character of the Old Course."