Held in the Library of Wales' Temple of Peace in Cardiff under the guardianship of the Welsh Centre for International Affairs, the Welsh Church Leaders' Peace Memorial - signed by 22 heads of churches across Wales' denominations - was an appeal from the church movements of Wales to the churches of America, calling for their support for the United States to join and lead the League of Nations: "A memorial from leaders of religious bodies in Wales to the federal council of the churches of Christ in America."
The Churches' petition built on the success of the previous years' Welsh Women's Peace Memorial, presented in New York in March 1924. The WLNU sought to maintain momentum from this high profile campaign; congregations Wales-wide wanted to express their support for the League, and church leaders wished to put 'faith into action'. They saw an opportunity to influence through the American Churches' annual gathering in Detroit; this memorial was conveyed there in December 1925 by Rev Gwilym Davies, Hon Director of The Welsh League of Nations Union, and was received with a standing ovation from the religious leaders of the United States.
The memorial can be viewed today in the Library of Wales' Temple of Peace, under the dare of WCIA (the Welsh Centre for International Affairs), present day successor to the WLNU.