The images created as part of "One heart, One tree" were projected onto monuments in Paris during the United Nations Climate Conference (COP21) in December 2015. Buildings included the Eiffel tower and the Hôtel de Ville, among others. Spectators used their smartphones to participate in creating the "forest of light", while listening to the music of Philip Sheppard. A heartbeat sensor on the smartphone gathered data that was used to generate a unique digital tree, that was then projected onto the building. 52,677 trees were created during the six days in which the participatory art project was displayed. For each computer-generated tree, a real tree will be planted, in Europe, Latin America, Africa or Asia, enabling participants in the art installation to also become participants in reforestation. The cost of planting is covered by the participants' donations (about $11 U.S.). Plans are underway to take the project to other cities around the world.