Air Operations, CBI

• 8 490th Medium Bomb Squadron B-25s attack a bridge spanning the Mu River and a bridge at Changtu.
• 12 10th Air Force A-31s attack Daletme.
• 12 459th Fighter Squadron P-38s attack the airfield at Shwebo.
• B-25s and fighter bombers mount nearly 150 sorties against numerous targets in the Mogaung Valley.

• 12 308th Heavy Bomb Group B-24s attack Lungling and Tengchung.
• 6 341st Medium Bomb Group B-25s and 12 14th Air Force P-40s attack barracks and warehouses at Chenyangi.
• 30 51st Fighter Group P-40s support Chinese Army forces on the Salween River front.
• 25 CACW and Chinese Air Force P-40s attack tanks, motor vehicles, and troops at Chueh-shan and Loning.

• 36 10th Air Force A-31s attack targets at Moirang and near Bishenpur and Homalin (Burma).

Air Operations, East Indies

• 380th Heavy Bomb Group B-24s attack Halmahera.
• V Bomber Command B-25s attack Larot (Ceram) and Saumlakki (Molucca Islands).

Air Operations, Europe

• 17 Mosquitos are sent on Oboe calibration tests to targets in France, 4 aircraft bomb Mondeville and 2 Orly; the others do not bomb. There are 7 RCM sorties.
• There are no losses.

Air Operations, Japan

2 28th Composite Group B-25s sink a ship in the Kurile Islands during the day, and 2 other B-25s sink a second vessel just before midnight.

Air Operations, New Guinea

• XIII Bomber Command B-24s attack Bosnik on Biak Island.
• V Bomber Command Force B-24s, B-25s, A-20s, and V Fighter Command fighter-bombers mount more than 100 sorties throughout the day against targets from Hansa Bay to Wewak.
• During the day, flights of 3rd Light Bomb Group A-20s orbit the landing area and provide close support as needed, and V Bomber Command B-25s rigged out as control planes spot targets and direct air and even artillery and shipborne fire missions.
• During the night, several Japanese bombers mount an ineffective raid against ground targets in the Hollandia area.

Admiralty Islands

The 6th Army announces that the campaign is over. The fortified bases at Kavieng, New Ireland and Rabaul, New Britain are entirely surrounded by Allied forces. They will remain this way until the end of the war, escaping invasion owing to the US policy of avoiding Japanese strongholds if they can be bypassed and isolated instead. The Americans have lost 326 dead and 1,189 wounded, the Japanese 3,820 dead and 73 prisoners.

Burma

In the Myitkyina area the Chinese and Americans defend the airfield against Japanese counter-attacks, while units of the Chinese 30th and 50th Divs begin the assault on the city and capture the railway station.

Diplomatic Relations

The UK and the USSR agree that Rumania will be in the Soviet sphere of influence while Greece will be in the British sphere.

Germany, Command

Berlin announces that Field Marshal von Rundstedt is to be Commander-in-Chief West with Field Marshals Erwin Rommel and Johannes Blaskowitz his subordinates at Army Groups B and G in the north and south respectively. This arrangement is by no means ideal as Rommel and von Rundstedt quickly develop diverging views on the necessary strategy and both put them to Hitler, who establishes a poor compromise.

Italy

The Monte Cassino abbey is finally taken by the Polish 12th Podolski Regiment of the 3rd Carpathian Div. At 10:30a.m. the Polish flag flies from what remains of the Benedictine monastery. The improvised Polish flag was hastily sewn with pieces of it coming from a Red Cross flag and soldiers' handkerchiefs. Men from 15 nations participated in the 4-month long battle. About 20,000 were killed and another 100,000 wounded.

Southwest of Monte Cassino in the Liri Valley Gen Burns' Canadian I Corps is now up to the 'Senger' Line before Pontecorvo. The 'Senger' Line, or 'Senger Bolt', is formerly the 'Hitler' Line which is a series of fortified positions on the line Piedmonte-Aquino-Pontecorvo. On their left the French advancing in the direction of Pico, and on the coast the Americans, are meeting equally solid opposition.

Mediterranean

In sinking a ship from the convoy HA-43, U-453 records the last success by a German submarine in the Mediterranean.

New Guinea

After a powerful air and artillery preparation, the main body of the 163rd Inf Regt (Gen Jens Doe) is landed on Insoemar Island, where Wadke airfield is sited, taking the greater part of it before evening and driving off the Japanese counterattacks during the following night.

Turkey

Martial law is declared after fascist disturbances.

Images from May 18, 1944

Infantry of the East Surrey Regiment Enter the Ruins of Cassino, Italy, 18 May 1944

Two German Paratroopers Fighting among the Ruins of the Monastery

Troops of the 2nd Polish Corps Throwing Grenades at the Enemy during Heavy Fighting around Monte Cassino

Sherman Tanks and Infantry in the Ruins of Cassino, Italy, 18 May 1944

A low aerial View of the Monastery Showing its Complete Destruction

British troops examine a knocked-out German StuG III assault gun near Cassino, Italy, 18 May 1944. Two 75mm AP rounds from a Sherman tank have neatly penetrated its front armour

A Knocked-out German StuG III Assault Gun

Mule Pack on way to the Front Passes Wrecked German tank. Fifth Army, Castelforte area, Italy, 18 May 1944

Allied infantrymen make their way over the ruins of Cassino in Italy, on the day that it fell to the Allied attack, 18 May 1944

Passing through the Ruins of Cassino

Soldiers examining a knocked out Sherman tank, amongst the ruins at Cassino, Italy, 18 May 1944, the day it fell to the Allies

Examining a Knocked Out Sherman tank

Members of the 4 NZ Armoured Brigade alongside a Sherman Tank, after the Capture of Cassino, Italy, 18 May 1944

Entering the Ruins of Cassino

A Sherman tank and jeep of the 4th Brigade entering the ruins of Cassino. The monastery of Cassino had formed the focal point of the German Gustav Line which they had successfully defended since November 1943. The fourth offensive led by Polish and British troops secured Cassino for the Allies and caused the Germans to retreat north of Rome, which was then declared an 'open city'.

A 4.2-inch mortar of 1st Infantry Brigade's support group, firing in support of the 5th Northamptonshire Regiment in the Anzio bridgehead, Italy, 18 May 1944

A 4.2-inch Mortar of 1st Infantry Brigade's Support Group