Italy
Sicily and Italy.
The reference was to Italy .
EFEWFEW
Gallipoli is found in the European part of Turkey with the Aegan Sea to the west. Winston Churchill explained it as "The soft underbelly of Europe".
Italy
The soft underbelly of the Axis was Churchill's concept of Italy and it was chosen as the country the Allies would go after first (on the European Continent)
Churchill
It became the steeping stone into occupied Europe from the South. [As Churchill called it in the planning stage "the chance to strike at soft underbelly of Fortress Europe]
If Istanbul could be captured, access to the Black Sea would be gained opening up the so called Soft Underbelly of Europe.
It was the landing of British & American forces in French North Africa. It would lead to the Invasion of Italy. As Churchill described it the soft underbelly of Europe.
The soft underbelly of the Axis Powers was Italy. The allies (US-led) launched the invasion of Scicily and Italy in order to knock it our of the war.