These photos prove WWI-era naval architects did acid

This photograph shows the submarine's four bow torpedo tubes and hydroplane on the port side. | Tyne & Wear Archives & Museums

The following images, provided by Tyne & Wear Archives, show the heart of a World War I German submarine that sank in 1918 after it was rammed by a torpedo boat destroyer.

During WWII, Germany built 1,162 destructive "U-boats," which is short for the German word "Unterseeboot," or undersea boat. By April 1917,430 Allied and civilian vessels were sunk by German U-boats.

Tyne & Wear Archives & Museums

Here are photos from the control room of a salvaged UB-110 submarine.

This photo shows the manhole to the periscope, hand wheels (for pressure), and valve gauges:

Tyne & Wear Archives & Museums

Here's the submarine's hydroplane gear, depth gauges, and fuel-tank gauges:

Tyne & Wear Archives & Museums

More hand wheels for managing air pressure and engine telegraphs:

Tyne & Wear Archives & Museums

The submarine's gyrocompass, steering control shaft, engine telegraphs, and voice pipes are visible in this photo:

Tyne & Wear Archives & Museums

The following two photos show the electrical portion of the control room:

This photo shows part of the control room and looks into the motor room and the torpedo room:

Here is the torpedo room: