Problem: The 1-mile-long (2 km) Breakwater in Plymouth Sound was designed by John Rennie in order to protect the fleet moving in and out of Devonport; work started in 1812. Numerous technical difficulties and repeated storm damage meant that it was not completed until 1841, twenty years after Rennie's death. In the 1860s, a ring of Palmerston forts was constructed around the outskirts of Devonport, to protect the dockyard from attack from any direction.
In kilometers, how long was the Plymouth Sound Breakwater?
The answer is the following: 2

Problem: During the Napoleonic Wars in the late 18th century and early 19th century, Napoleon annexed territory formerly controlled by the Habsburgs and Savoys. In 1798 he established the Helvetic Republic in Switzerland; two years later he led an army across the St. Bernard pass and conquered almost all of the Alpine regions.
When was the Helvetic Republic established?
The answer is the following: 1798

Problem: In 1930 Thuringia was one of the free states where the Nazis gained real political power. Wilhelm Frick was appointed Minister of the Interior for the state of Thuringia after the Nazi Party won six delegates to the Thuringia Diet. In this position he removed from the Thuringia police force anyone he suspected of being a republican and replaced them with men who were favourable towards the Nazi Party. He also ensured that whenever an important position came up within Thuringia, he used his power to ensure that a Nazi was given that post.
Who did Frick replace republican police with?
The answer is the following: men who were favourable towards the Nazi Party

Problem: 155th Street starts on the West Side at Riverside Drive, crossing Broadway, Amsterdam Avenue and St. Nicholas Avenue. At St. Nicholas Place, the terrain drops off steeply, and 155th Street is carried on a 1,600-foot (490 m) long viaduct, a City Landmark constructed in 1893, that slopes down towards the Harlem River, continuing onto the Macombs Dam Bridge, crossing over (but not intersecting with) the Harlem River Drive. A separate, unconnected section of 155th Street runs under the viaduct, connecting Bradhurst Avenue and the Harlem River Drive.
In what year was the viaduct along 155th Street constructed?
The answer is the following:
1893