and the Lawn Tennis Association. In 2014, Catherine wrote the foreword for Living in the Slipstream: Life as an RAF Wife, whose proceeds raised money for charity. Since acquiring patronage of the RAF Cadets, she has made visits to their base in Cambridgeshire and celebrated their 75th anniversary in 2016. In January 2018, locks of her hair were reportedly donated to the Little Princess Trust, a charity which makes wigs for children diagnosed with cancer. In February 2018, she became the patron of the Royal College of Obstetricians and Gynaecologists. She also launched Nursing Now, a three-year worldwide campaign to raise awareness about the profile of nurses. She has written of her family ties with nursing and that both her grandmother Valerie Middleton and her great-grandmother Olive Middleton were VAD nurses for the British Red Cross. During the COVID-19 pandemic, Catherine undertook many in-person and virtual engagements supporting National Health Service workers. In May and June 2020, William and Catherine, alongside their children, delivered food parcels made on the Sandringham Estate to local isolated pensioners during lockdown. She discreetly volunteered with the Royal Voluntary Service during the COVID-19 pandemic. Catherine has called herself an "enthusiastic amateur photographer" and has taken official portraits of her children, as well as other members of the royal family. In 2019, she supported workshops run by the Royal Photographic Society in partnership with Action for Children to highlight the effect of photography in expressing thoughts in young people. As patron of the Royal Photographic Society she and other photographers took part in an exhibition to mark the 75th anniversary of the end of the Holocaust. Photos taken by Catherine of the Holocaust survivors were later included in an exhibition at the Imperial War Museum. With the National Portrait Gallery, Catherine curated an exhibition of Victorian photography, with a thematic focus on childhood. In May 2020, she launched "Hold Still", a project to capture people's life during lockdown, which garnered 31,000 submissions. In July 2020, the exhibition was released, with the final 100 photographs being displayed online. In October 2020, the portraits were displayed on 112 public sites, including billboards, murals, and posters, across 80 towns and cities. The online exhibition collected over 5.2 million page views. The photographs were published in a book on 7 May 2021, titled Hold Still: A Portrait of Our Nation in 2020, with a foreword written by Catherine. In May