Air Operations, Carolines

307th Heavy Bomb Group B-24s attack the Truk Atoll.

Air Operations, CBI

• 1 7th Heavy Bomb Group B-24 attacks Mandalay.
• 21 10th Air Force A-31s attack a bridge at Manipur and Japanese Army ground troops around Homalin.
• Several A-31s attack targets in the Arakan coastal region.
• B-25s and fighter-bombers mount more than 120 sorties in the Mogaung Valley.

Air Operations, Central Pacific

US carrier aircraft from Task Group 58.6 conclude their attacks on Marcus Island.

Air Operations, Europe

Operation CHATTANOOGA CHOO-CHOO begins, the systematic attack by Allied aircraft on trains in Germany and France.

• 510 Lancasters and 22 Mosquitos of Nos. 1, 3, 5 and 8 Groups carry out the first large raid on Duisburg in a year. The target is covered in cloud, but the Oboe skymarking is accurate and much damage is caused in the southern areas of the city.
• 29 Lancasters are lost.
• 70 Lancasters and 37 Halifaxes lay mines in the Frisians, Heligoland, the Kattegat and Kiel Bay.
• 3 Lancasters are lost.

• 25 Mosquitos are sent to Hannover, 8 to Courtrai, and there are 28 Serrate and 7 Intruder patrols and 9 RCM sorties.
• There are no losses.

• 25 1st Bomb Division B-17s and 99 2nd Bomb Division B-24s, respectively, attack V-weapons sites at Marquise/Mimoyecques and Siracourt with the aid of GH blind-bombing equipment.

• During their first missions posted under Operation CHATTANOOGA CHOO-CHOO, VIII Fighter Command fighters ranging over Germany destroy 91 locomotives of 225 attacked. Targets of opportunity, including many airdromes and rail bridges, are also attacked by the fighters. 8th and 9th Air Force fighter pilots down 21 Luftwaffe aircraft, including as many as 8 trainers and 4 or 5 other noncombatants, between 1220 and 1335 hours.
• 27 fighters are downed by enemy action; 26 pilots missing

• 50 IX Bomber Command B-26s attack the Abbeville/Drucat Airdrome.
• An estimated 500 9th Air Force P-47s and P-51s attack locomotives and rail cars throughout France. 9th Air Force fighters and fighter-bombers account for 46 locomotives destroyed and another 11 probably destroyed, plus assorted other damage to locomotives, rolling stock, and rail facilities.

• 12th Air Force B-25s and B-26s attack several roads and bridges in north-central Italy.
• XII TAC A-20s attack a German Army bivouac.
• XII TAC fighter-bombers maintain pressure on German Army forces in the battle areas and also range throughout central Italy to attack rail and other comunications targets.

Air Operations, New Guinea

• V Bomber Command B-24s and A-20s, and V Fighter Command P-38s, attack Biak Island and targets along the Moemi River.
• 380th Heavy Bomb Group B-24s based in Australia attack the airfields at Manokwari, Urarom, and Moemi.
• 12 3rd Light Bomb Group A-20s attack the Kamiri airfield on Noemfoor.
• 5th Air Force B-25s, A-20s, and fighter- bombers attack numerous targets between Hansa Bay and Wewak.

Burma

The Japanese counterattack; a battalion of American Marauders repulses enemy attacks along the Mogaung road, but is then halted by the Japanese when it tries to advance.

CBI

A Japanese counterattack is stopped by the 3rd Battalion of the Marauders. The men are so weak from illness that many collapse in the middle of the fighting. About 75 to 100 men of the Marauders are being evacuated every day for sickness.

Italy

An infantry battalion of the US 85th Div is sent by sea from Gaeta to Sperlonga and lands without difficulty. The American 88th Div captures Monte Calvo and Cima del Monte, while the French positions have to withstand fierce German pressure. The US forces also take Fondi and the French Campodimele. In the Liri Valley and around Pico, the German opposition is stronger, but the Allies are bringing forces forward for another blow.

Gen Clark, Commander of the US 5th Army, orders Gen Lucian Truscott, commanding the US VI Corps, dug in on the Anzio beachhead, to launch his attack against the German positions at 6:30a.m. on May 23. The British 8th Army will attack in force simultaneously from the north to breach the 'Senger' Line and penetrate into the valley of the Liri River.

Mediterranean

U-453 attacks Convoy HA-43 late afternoon on the May 19. The Italian ships Urania, Danaide and Monzambano are sent to the are to search for the U-boat. They are reinforced by 3 British ships, Termagant, Tenacious and Liddesdale. They begin their search at 10:30am on the 20th. Contact is made about an hour later and the destroyer make 11 attacks. They stay in the area knowing the U-boat will have to surface eventually for air. Very early on the morning of the 21st, the U-boat surfaces and is destroyed by gunfire.

U-453

New Guinea

The beachhead at Arare is reinforced and offshore at Wadke the airfield is repaired and reopened by US engineers.

Pacific

An accidental explosion occurs in tank landing ship LST-353 as she is being loaded with mortar ammunition at West Loch, Pearl Harbor. The cataclysmic blasts result in the losses of the following landing craft: LST-39, LST-43, LST-69, LST-179, LST-353, LST-480, LCT-961, LCT-963, LCT-983, 17 tracked landing vehicles (LVTs) and 8 155-mm guns.

United States, Home Front

An explosion on a landing craft in Pearl Harbor, Hawaii kills 127 and injures 380. LST-43, LST-69, LST-179, LST-353 and LST-480 are lost in the explosion.

Images from May 21, 1944

Accidental Ordnance Blast

The Burned Hulk of LST-39

Dummy Sherman Tank in the Anzio Bridgehead

Wrecked German Artillery Weapons

German Coastal Gun in Gaeta, Italy

Debris of Gaeta, Italy Harbor

Ships Burn at West Loch, Pearl Harbor

Destroyed German Pill Box in Cassino

Fires Continue through the Night

Damaged German Tank in Castelforte, Italy

Advancing to the Front in Castelforte

German Artillery Weapon in Castelforte, Italy