Kenneth C. Brugger discovered the long-unknown winter destination of the monarch butterfly in the mountains of Mexico. From 1937, for 38 years, Canadian zoologist Freud Urquhart patiently investigated to establish the route and destination of the insects. Using tags on the wings of some butterflies, he followed their migration trails to Mexican territory. Brugger, one of Urquhart's helpers, after a long period of traveling in the center of Mexico, found the first butterfly refuge. Within the territory of only 200 square meters, there are around 20 million butterflies. The area was cold and covered with oyamel trees and pine trees, a few kilometers from rural towns.

Construction began on the Brooklyn Bridge to cross the East River, New York City, USA, with a single span, a breadth of 1,600 feet navigable water. The 13 year project was started by John Roebling, and after his death, completed by his son Washington Roebling. It was opened on 24 May 1883. What was then regarded as the greatest engineering feat still stands in service today, and remains the world's only stone-towered, steel cabled bridge. Twice the size of the Niagara Suspension Bridge and four times the longest non-extension spans then attempted, the total length of this colossal structure is 6,927 ft. The road bed is 80 feet wide, at an elevation of 186 feet above high water.«