New shock for US army: biggest conventional bombs useless against Iran's new bunker design?

America’s biggest conventional bunker‑buster bombs are no longer enough for Iran’s newest underground sites. After B‑2s hit Fordow with GBU‑57s and Tehran dug even deeper, the Pentagon has rushed DARPA into developing next‑generation penetrators. With China and North Korea also expanding tunnel networks, Washington is racing to design bombs that can reach buried targets before the next war does.