On December 17, 1985, the UN General Assembly adopted resolution 40/212, inviting governments to annually observe December 5 as International Volunteer Day for Economic and Social Development. Since then, governments, UN agencies, and civil society organizations have joined together each year to mark the occasion. The day celebrates volunteering in all its forms, from grassroots community service to participation in disaster relief and humanitarian response around the world. It aims to raise awareness of how volunteers—estimated at hundreds of millions worldwide—drive sustainable development, and to encourage more people to get involved in volunteer work. Events typically include campaigns honoring volunteers, community volunteering drives, and stories highlighting the real difference volunteers make in people's lives. Many organizations also use the day to launch new calls for young people and institutions to join structured volunteer programs.