As negotiations between the U.S. and Iran over Tehran's nuclear program continue, American aircraft carriers are at the forefront of a major U.S. military buildup in the Middle East. Subscribe to ABC News on YouTube: https://abcnews.visitlink.me/59aJ1G ABC News is your daily source of breaking national and world news, exclusive interviews and 24/7 live streaming coverage. Download the ABC News app for the latest headlines and alerts: https://abcnews.go.com/devices Watch 24/7 coverage of