The Battle of Mani-Mani, a failed American landing attempt west of Havana, was the final engagement of the Spanish-American War in Cuba.

On July 23, Lieutenant Heard anchored his force at the mouth of the Mani-Mani River and began unloading supplies intended for the Cuban insurgents operating in northwestern Cuba, unaware that the Spanish had discovered his presence and assembled a large force of cavalry in the environs.

Catching the Americans off guard, Spanish cavalry advanced out onto the beach and opened fire upon the landing parties. Heard ordered his men to take cover and return fire. Pounded by accurate American volleys, the Spanish drew back into the jungle.

Lieutenant Heard used the temporary respite to order an immediate retreat, evacuating his wounded into the Wanderer and preparing to lift anchor just as the Spaniards reappeared, unleashing a hail of fire at those on the deck.

For his remarkable calm and courage in the heat of battle at Mani-Mani, John Heard was later awarded a Medal of Honor noting, "after two men had been shot down by Spaniards while transmitting orders to the engine-room on the Wanderer, the ship having become disabled, this officer took the position held by them and personally transmitted the orders, remaining at his post until the ship was out of danger."