It was a day full of emotion, surprises, and tension. It was also a day of numbers, and we've got them.
Seconds trimmed from the previous best ever decathlon 400m time by Ashton Eaton when he ran 45.00 in the fifth event today.
Points by which Eaton trails his first-day total from his world record decathlon in 2012.
Points by which Ashton Eaton leads the decathlon at the end of the first day.
The year the previous best mark in the decathlon 400m (45.68) was run, by Bill Toomey at the Mexico City Olympics.
The first year the Olympic 400m title was won faster than 45.00.
The last time 45.00 would have qualified to the individual 400m final.
Women's 200m final
Number of previous races with three women under 22 seconds.
Women who have ever run faster than Dafne Schippers' 21.63 for 200m.
National records set (Schippers for the Netherlands, Dina Asher-Smith 22.07 for Great Britain).
Number of global medals won by Veronica Campbell-Brown (third in 21.97).
Women's 100m hurdles final
Sisters in the final; winner Danielle Williams and her older sister Shermaine Williams, who placed seventh in 12.95.
Hundredths separating third place (Alina Talay in a Belarusian record of 12.66) and fifth place (Tiffany Porter in 12.68).
Hundredths separating first place (Danielle Williams in 12.57) and fourth, out of the medals (Brianna Rollins in 12.67)
Men's 110m hurdles final
Hurdles over which Russia's Sergey Shubenkov led before outsprinting the field to the finish line in 12.98.
Previous medals for Jamaica in the 110m hurdles, before Hansle Parchment's silver in 13.03.
Previous medals for Russia (Bronze for Shubenkov in 2013).
Days until bronze medallist Aries Merritt goes in for kidney surgery.
Steps after which defending champion David Oliver considered himself "doomed".
Women's long jump final
National records set which didn't win (Shara Proctor's 7.07m for Great Britain, and Ivana Spanovic's 7.01m for Serbia).
Number of times a jump beyond seven metres would still not win the women's long jump at the World Championships.
Round in which Tianna Bartoletta took the long jump lead with her 7.14m leap.
Years since Bartoletta's previous world long jump title (competing as Tianna Madison).
Women's 20km race walk
Number of gold medals won by China in the championships, after the 20km race walk.
Number of silver medals won by China, after the 20km race walk.
Gap between first (Liu Hong) and second (Lu Xiuzhi) in the 20km race walk, in hundredths of a second. Both were listed with times of 1:27:45 in the results.
Seconds Liu and Lu's second 10km of race walking was faster than their first.
Parker Morse for the IAAF