Big Bertha is the name of a type of super-heavy howitzer

Howitzer

A howitzer is a type of artillery piece characterized by a relatively short barrel and the use of comparatively small propellant charges to propel projectiles at relatively high trajectories, with a steep angle of descent...

 developed by the famous armaments manufacturer Krupp

Krupp

The Krupp family , a prominent 400-year-old German dynasty from Essen, have become famous for their steel production and for their manufacture of ammunition and armaments. The family business, known as Friedrich Krupp AG Hoesch-Krupp, was the largest company in Europe at the beginning of the 20th...

 in Germany on the eve of World War I

World War I

World War I , which was predominantly called the World War or the Great War from its occurrence until 1939, and the First World War or World War I thereafter, was a major war centred in Europe that began on 28 July 1914 and lasted until 11 November 1918...

. Its official designation was the L/12 (i.e., the barrel was 12 calibre

Caliber (artillery)

In artillery, caliber or calibredifference in British English and American English spelling is the internal diameter of a gun barrel, or by extension a relative measure of the length....

 in length) 42-cm (16.5 inch) Type M-Gerät 14 (M-Equipment 1914) Kurze Marine-Kanone ('short naval gun', a name intended to camouflage the weapon's real purpose).
The howitzer was mainly designed by Krupp's Director of design, Professor Fritz Rausenberger, and his predecessor, Director Dräger.