The island of Betio was two miles long and a half a mile wide, and it was covered with numerous defenses and barriers such as concrete bunkers, seawalls, a trench strip, machine guns and tanks, and shallow reefs around the island that were covered with barbed wire and mines. It was the first American offensive in this critical Pacific region, and the first time they had met major resistance from the Japanese to their amphibious landing, which uses naval ships to protect the soldiers.
18,000 marines came on aircraft carriers, battleships, cruisers, and destroyers. Many parts of the attack were delayed in their attack, causing them to dodge Japanese fire. Ships also got stuck on the barrier reefs in shallow waters, so Marines had to wade ashore, defenseless, losing supplies, and costing many live. By the end of the day 5,000 marines had made it ashore and 1,500 had lost their lives. This battle started the new war tactic of “Atoll War” which relied on heavy invasion and bombardment by battleships and airplanes.