Although the pictures were in storage, Clark kept the National Gallery open to the public during the war, hosting a celebrated series of lunchtime and early evening concerts. They were the inspiration of the pianist Myra Hess, whose idea Clark greeted with delight, as a suitable way for the building to be "used again for its true purposes, the enjoyment of beauty." There was no advance booking, and audience members were free to eat their sandwiches and walk in or out during breaks in the performance. The concerts were an immediate and enormous success. "The Musical Times" commented, "Countless Londoners and visitors to London, civilian and service alike, came to look on the concerts as a haven of sanity in a distraught world." 1,698 concerts were given to an aggregate audience of more than 750,000 people. Clark instituted an additional public attraction of a monthly featured picture brought from storage and exhibited along with explanatory material. The institution of a "picture of the month" was retained after the war, and, at 2018, continues to the present day.