After their initial inclusion on the US Tentative List, focused efforts to advance either the Serpent Mound or the Hopewell Ceremonial Earthworks nomination, or both, got seriously underway via a series of meetings with key stakeholders beginning in 2009. An early step was to bring the sites to the attention of international leaders and experts in UNESCO, ICOMOS, and NPS-OIA, and to seek their advice about how to proceed.