On a coral island roughly half the size of Central Park, nearly 6,400 men died in 76 hours in November 1943. This episode dissects the assault on Betio Island and how it forged modern amphibious warfare.

We explore why this tiny speck of the Gilbert Islands was a strategic roadblock to Japan, how sand-and-log bunkers absorbed naval shells, and how an unexpected neap tide left Marines wading 500 yards into machine-gun fire.

• Why Betio’s airfield blocked the path to the Marshalls and Marianas
• How palm-log and sand pillboxes outperformed solid concrete
• The neap tide that grounded Higgins boats on the reef
• Severed communications and the death of Admiral Shibazaki
• How the disaster created the Navy’s underwater demolition teams