Evangelical Christians have been granted permission by the Communist government of Cuba to hold large rallies there in May and June.
Churches will be permitted to hold local open-air gatherings of the "Cuban Evangelical Celebration" in May, the Assemblies of God news agency reported.
Organizers hope one of the June rallies will be held in Havana's Revolution Square, where Pope John Paul II held his largest Mass last year.
"Given what we know at this time about church growth on the island, if the right circumstances come together, half a million people might come to the Havana celebration alone," said the Rev. Richard Nicholson, regional director of Latin America and the Caribbean for the Assemblies of God's Division of Foreign Missions.
The Assemblies of God is one of the largest evangelical churches in the country.