71. Despite being preferred urban gathering places, two-thirds of the independent bookstores in the United States have closed for good during their lifetimes.

72. Astronauts have always spent well over a year in a single space flight.

73. Lou Gehrig's record for most consecutive baseball games played has never stood in their lifetimes.

74. Genomes of living things have always been sequenced.

75. The Sistine Chapel ceiling has always been brighter and cleaner.