The spiritual leader of the world's 250 million Orthodox Christians is in the U.S. to meet with national leaders about religious freedom and environmental issues.
Ecumenical Patriarch Bartholomew is known as the "green patriarch" for his environmental advocacy.
In a meeting with President Obama, the two discussed the impact of Hurricane Katrina on New Orleans, La.
Bartholomew said they also talked about the need for religious liberty in all nations, including Muslim Turkey, where his patriarchate is based.
Julia Duin, religion editor at the Washington Times, has been covering the patriarch's visit to the United States.
What are Protestant and Roman Catholic leaders saying about preserving the environment? Click play to hear Duin's answer.