What is associated with: between 1931 1970 millions learned to read using books featuring this brother sister their dog spot?

What is associated with: between 1903 1905 this norwegian discovered the exact location of the north magnetic pole? What is associated with: between 1913 1932 canada dug a new deeper version of the welland canal that connects these 2 g… What is associated with: between 1919 1925 he made several versions of bird in space in marble bronze? What is associated with: between 1921 51 the cubs held spring training on this island owned by wrigley near la? What is associated with: between 1937 1942 he successfully defended his heavyweight title 21 times? What is associated with: between 1937 1950 this american boxer fought in 27 heavyweight title fights winning 26? What is associated with: between 1951 1977 this automotive foundation pumped about 290 million into public tv? What is associated with: between 1954 1980 the average weight of this annual selectee went from 132 pounds to 117?