Egyptian Naval Day is observed in Egypt every October 21 to commemorate the sinking of the Israeli destroyer INS Eilat by the Egyptian Naval Force in 1967. This event marked a significant milestone in modern naval warfare, as it was the first instance of a navy sinking a ship using anti-ship missiles. The destroyer, originally a Z-Class ship known as HMS Zealous in the Royal Navy, was active during notable conflicts such as the Suez Crisis and the Six-Day War. On October 21, 1967, while on patrol in international waters off Port Said, INS Eilat was struck by missiles launched from an Egyptian Komar-class missile boat, leading to its sinking. The day is celebrated annually to recognize the advancements in naval weapons and strategy introduced by this event. Although it is a significant day in Egypt's naval history, it is not a public holiday, and government offices, schools, and businesses remain open.