Iran’s paramilitary Revolutionary Guard launched underground ballistic missiles on July 29 as part of an exercise involving a mock-up American aircraft carrier in the Strait of Hormuz, highlighting its network of subterranean bases. Iran's elite Revolutionary Guards fired ballistic missiles from underground for the first time as part of an annual military drill. Videos released show clouds of dust before the missiles streaked into the sky. Military drill in the Gulf, which began on July 28, comes at a time of high tension between Tehran and Washington. Footage also showed a missile striking a target resembling an American missile defense system known as a Terminal High-Altitude Area Defense, or THAAD.