Clad in black armbands, many among the 37,500 participants at today's London Marathon will be running with the horrific events of the Boston bombings in their minds.
Among them will be a handful of Singaporeans, determined to carry on running in the face of terror.
Lim Han Chee, 45, will be making his debut in London.
He said: "It will be a great show of solidarity and humanity to run and finish, with Boston in our hearts. What happened there will not put me off this race or any future races."
The civil servant, who has participated in more than 20 overseas races, is not alone. From London to Langkawi, a growing number of locals are flocking overseas to compete in marathons.
Some venture as far as New York, one of the five major 42.195km races on the calendar, along with the London, Chicago, Berlin and Boston races.
The Big Apple race has seen a rise in Singaporean participation from only eight in 2010, to 24 last year.
Said Lim, who has also ventured to the Berlin and Paris marathons in the past two years: "I prefer to go to countries with colder climates, because it has always been a challenge for me to overcome the heat."
However, races held in Asia-Pacific countries are still more popular, owing to their geographical proximity and cheaper costs.
The Gold Coast Airport Marathon (GCAM) ranks among the most popular. From only 24 Singaporeans taking part in 2007, it has grown to a record 311 last year.
Its popularity is owing to Tourism and Events Queensland's efforts to reach out to local runners, largely through local running group Fat Bird, which helps to conduct pre-GCAM training sessions.
Said Anthony Sum, founder of Fat Bird, which has an active membership of 800: "Gold Coast is popular because of its scenic route which is relatively flat, and also its cool weather that ranges from about 12 to 15 deg C.
"This makes it a suitable course to clock a personal best (PB) time. About 80 per cent of runners whom I accompany clock a PB."
Other top regional races such as the Tokyo and Korea marathons have also gained a sizeable following, as they are regarded to be well-organised and have supportive crowds.
Tay Tze Siong, 45, was among a group of 169 Singaporeans who took part in the Tokyo Marathon last year.
He said: "When I ran there, it was a very fulfilling experience. There were no bottlenecks on the route and the race-pack collection queues were very smooth.
"The weather was cold, but many supporters still came out.
"They offered chocolates, and orange and apple slices along the way."
For Amy Wong, who has run more than 15 races overseas, her passion for marathons gives her a good reason to travel.
The 42-year-old quantity surveyor has completed more exotic races like the Medoc Marathon, which took her to the south-west of France.
Known for its red wine, the Medoc race sees its participants running through some of its 1,000-odd vineyards.
Said Wong, who ran in the 2010 edition: "I like to combine my marathon running with sightseeing and the race at Medoc was one of the most memorable for me.
"They even offered wine at the water points. We had to be careful not to drink too much that we wouldn't be able to run back."
For many, the very fact that overseas marathons provide a refreshing change from the local marathon routes is also a big draw factor.
Said Jennifer Lem, 37, who has completed in more than 20 marathons, including the Osaka, Honolulu and Sydney races: "Locally, the routes are quite boring. You already know where you are going to run - East Coast and the central business district area."
Some, like 53-year-old Mohanadas Kandiah, are simply addicted to the sport, and the handful of marathons available here annually are just not enough.
Mohanadas, or "Mohan Marathon" as he likes to be known, has completed over 200 marathons.
He said: "For me, it's all about passion. It doesn't really matter which country. It's about running."