I've been reading a great daily devotional called Voices of the Faithful: Inspiring Stories of Courage from Christians Serving Around the World. I didn't take it to Punta Cana so was trying to catch up by doing a couple of readings at once. It worked out that just as I was studying God's Power through Isaiah 40, I read two stories in a row about God's power in answering prayer. In the first story, two women in Africa stopped listening to a witch doctor and were blessed with pregnancies. In the second one, a missionary visiting a refugee camp in a remote area of Central Asia was asked to pray with a woman who was severely ill and blinded. The following day, two different organizations brought food and supplies. Two days later, the missionary returned to find the woman completely healed!
For more encouraging stories about God's work around the world, look up Voices of the Faithful. You won't be disappointed!