As a school girl, Brigadier-General Gan Siow Huang joined the Brownies and, later, the Girl Guides, for a taste of adventure.
"It gave me the opportunity to meet more people and have outdoor adventures. I have good memories of campfires, outdoor cooking and camping in the school field," recalls BG Gan, 43, the first woman Brigadier-General in the Singapore Armed Forces (SAF), who attained the one-star rank in 2015.
"There weren't so many such opportunities back then and my family couldn't afford them."
The third of four children, her father was a taxi driver and her mother a housewife.
In fact, the Guiding movement did more than give her the adventures she craved - it played a role in her high-flying career.
"Being in a uniformed group, I felt a strong sense of identity. I was interested in the experience of leadership and teamwork, which was useful in my career when I joined the SAF," says the commander of the Air Power Generation Command.
Guides share their experiences
The co-curricular activity is enriching. We get to meet Guides from other countries and learn about other cultures. We also learn things that will help us, even when we are grown up. I took part in a programme on caring for the elderly. When my friends and I visit them in hospital, we remind them of their grandchildren.
GIRL GUIDE REENA TEH, 14, a Secondary 3 student
I used to be very shy. I wouldn't make a lot of new friends because I didn't dare talk. Last year, I met some Brownies who were visiting from Kuala Lumpur. I had to interact with them when we painted kites and flew them at Marina Barrage. I've started talking more.
BROWNIE SOFEA ELLYSHA EDDY SAHRAN, 10, a Primary 4 pupil
Nine members of my family were either Girl Guides or Boy Scouts, including my parents. They used to tell me about singing campfire songs, tent-pitching and other activities they did. It wasn't so different from what we do now. I joined the Girl Guides in Secondary 1 and became the leader of a Guiding company in Secondary 3.
GIRL GUIDE CHERYL LIM, 15, a Secondary 4 student
As a Girl Guide patrol leader in upper secondary school, BG Gan led small teams organising campfires and outings.
More than the skills she learnt, such as tying knots, using a compass and identifying the stars in the sky, she says the values the Guiding movement hold dear, such as integrity and bravery, have stuck with her.
BG Gan is the mother of three daughters, aged five, 10 and 14. Her husband, Mr Lee Jek Suen, 43, is the assistant vice-president of strategic planning at Jurong Port.
The Guiding movement in Singapore marks its 100th anniversary on Saturdaynot only with a sense of tradition, but also with a view towards helping girls and women take on present-day challenges.
Ms Kim Lay Eng, Chief Commissioner of Girl Guides Singapore, says: "Some things about Guiding haven't really changed. Girls today still enjoy making friends. They learn to be independent and bond through unique Guiding experiences such as camping and sleeping outdoors."
Girl Guides Singapore has close to 9,000 members in more than 190 units of Brownies - for children in primary schools - and Guides, from Secondary 1 to 5, numbering more than other girls-only uniformed groups, says a Girl Guides Singapore spokesman. Guiding is offered as a co-curricular activity (CCA) in more than 55 per cent of primary and secondary schools.
Ms Kim says the movement stays relevant by keeping pace with the expectations of girls today and seeking to meet their future needs.
This includes having technology- based programmes, international opportunities and recognition for individual and group efforts.
Some changes in Guiding in Singapore over the years involve how girls apply the skills they learn. For instance, youngsters who learn about flora and fauna can share their knowledge with visitors to Gardens by the Bay and Jacob Ballas Children's Garden.
In the past, they would each have been tasked with creating a scrapbook.
Another contemporary programme is Free Being Me, in which girls are taught body confidence and self-belief.
Previously, a similar scheme would focus more on learning about personal hygiene and grooming.
On the Centenary Celebration World Thinking Day on Saturday, more than 5,000 girls, Guiding leaders and volunteers are expected to attend a commemorative event held at the Singapore Botanic Gardens, which features activities such as picnics and performances.
Girl Guides Singapore comprises not only Brownies and Guides, but also other units such as the Young Adults - for those aged 17 to 25 - and the Trefoil Guild for older women who were former Guides.
But one of the movement's most prominent advocates of nearly 60 years was never a Guide.
Puan Noor Aishah, 84, wife of Singapore's first President Yusof Ishak, became the first Asian president of Singapore Girl Guides Association as the movement was known then in 1959, the year Singapore attained self-government.
After Singapore gained independence in 1965, she was installed as the patron of the movement.
1910: The founder of the Boy Scouts, Robert Baden-Powell, formally launches the Guide movement after a few girls gate- crashed a Boy Scout event in London, pleading for "something for the girls".
1917: The Singapore Girl Guide movement started as part of the Malayan Girl Guides Association.
1935: A Guiding contingent was registered at St Andrew's Orthopaedic Hospital, signalling inclusivity. Six girls with tuberculosis made the Brownie Promise - a pledge to observe Guiding principles - while lying in their hospital beds.
1939: Girl Guides in Singapore contributed to the war effort in the European theatre of World War II, by knitting garments, collecting foil for recycling and packing bandages and other medical supplies.
1942-1945: Singapore Guiding activities were halted during the Japanese Occupation. Guides hid flags, Guiding literature, badges, awards and uniforms, which were used after the war.
1950: The Singapore movement sent its first overseas delegation of eight Guides to attend a camp in Perth, Australia, marking the start of more international interaction.
1956: As part of the movement's first Bob-A-Job Week - a fund-raising event - 800 Girl Guides scrubbed floors, cleaned windows and looked after babies.
1967: A Guide Company for deaf children was started.
1990: Singapore started hosting international Guiding events, beginning with the 27th World Conference of the World Association of Girl Guides and Girl Scouts.
1994: The first Annual Cookie Sale was launched, raising $137,000. Brownies and Guides sell tins of cookies every year to raise funds for the movement.
2000: President's Guide Awards were conferred on 25 Guides, a record number. The annual award is the highest accolade that a Boy Scout or Girl Guide can receive in Singapore.
Veteran Guiding leaders credit her with helping to raise funds for the movement when funding was scarce, and with helping to secure a plot of land for the Guiding headquarters in the Clemenceau area in the 1960s.
She says she supported the movement because she believed in its values, which she felt were especially relevant during Singapore's formative years.
"It was about how to bring up girls to be good citizens, to never think about race, to help one another. That was exactly what all of us needed," says the mother of three children, grandmother of 10 and great-grandmother of 12.
Even after her husband died in office in 1970, she has continued to support the movement, for example, by accepting invitations for dinners and fund-raising events.
"From time to time, I will help them because we are friends," says Puan Noor Aishah, who has an award for Brownies and Guides named after her, and is a recipient of the Laurel Leaf award for distinguished service to the movement.
The Guiding movement also remains in the heart of former Girl Guide, Ms Chua Sock Koong, 59, group CEO of Singtel. She says Guiding has helped her in her career.
"I'd like to think the Guides motto - Be Prepared - has somehow stayed with me all these years."
Training in her youth helped in Everest feat
The foundations for the mental and physical resilience that Ms Lee Li Hui needed to climb Mount Everest was laid when she was a Girl Guide.
She says: "Guiding laid the foundation for making one more confident in the outdoors."
Ms Lee, 35, was the first Singapore woman to reach the peak of Mount Everest, the world's highest mountain at 8,848m, in 2009. She was part of the Singapore Women's Everest Team, the first all-female expedition from Singapore to scale the summit.
Training on a demanding schedule for five years before their feat was a mental challenge because they did not know if they would be selected from an initial team of 28 members, says Ms Lee, a product innovation manager in the reinsurance industry.
The training took place most days of the week and included climbing a 30-storey HDB block several times, carrying backpacks weighing about 20kg, with 5kg ankle weights strapped on.
On the mountain, steely nerves were also needed to keep climbing in minus 40 deg C conditions, where "one's toes and fingers were always cold to the point of pain", she says.
The expedition team was whittled down to six members, five of whom made it to the top of Everest. One team member did not because of illness.
Ms Lee, who is married to a 36-year-old professional in the oil and gas industry, has been drawn to outdoor challenges since her youth. In 2013, she crossed 560km of Greenland in icy conditions on skis, a feat she accomplished with her friend, Ms Jane Lee, who led the all-woman Everest expedition.
Since Everest, Ms Lee Li Hui has also climbed to the summit of Aconcagua in Argentina, the highest peak in South America, in 2011.
Ms Lee, who has no children, recalls meeting her fellow guides frequently after school ended to plan annual campfires and other activities.
"I remember soaking firewood in kerosene, which is no longer the practice now. We had splinters in our hands and it made us feel rugged," she says with a smile.
"When you're mountaineering, you put your life in the hands of one another. Towards the end of the Everest climb, it was the commitment to the team goal that drove me. It was not letting others down."
• Commemorative stamps featuring four prominent women associated with Guiding will be sold at the Singapore Botanic Gardens gift shops on Saturday and thereafter at the Guide Shop, 9 Bishan Street 14. The stamps include wartime heroine Elizabeth Choy; President Yusof Ishak's widow, Puan Noor Aishah; Brigadier-General Gan Siow Huang; and mountaineer Lee Li Hui. For online orders, go to www.girlguides.org.sg.
Correction note: In our earlier story, we said that Aconcagua in Argentina is the world's second-highest peak after Everest. This is incorrect. We apologise for the error.