Event where the number 12 is important, and a feature of 12 two-word answers in this puzzle

Question:

Length:

Similar Crossword Questions:

Number of times this puzzle's theme word appears diagonally in the grid (to complete the puzzle, shade those words plus the Down answers that begin where they meet)
1987 market crash, and this puzzle's title, whose first word can precede each word in the starred answers
Word replaced in three answers in this puzzle
Word that goes after the start of and before the end of the five longest answers in this puzzle
Number inaugurated into this puzzle's theme answers
Coastal irregularities, and word anagrammed in this puzzle's four longest answers
Radio studio feature, and what each of this puzzle's four other longest answers literally is
The last word of this puzzle's five longest answers is a type of one
Weather Channel feature (it's the puzzle theme found in a quintet of answers)
TV feature, and a clue to six other answers in this puzzle
Action hero's garb, and what each first word in this puzzle's four longest answers is
Word separated in this puzzle's six longest answers
Word needed to be added to 12 appropriately placed answers in this puzzle for their clues to make sense
The word, as suggested by the saying formed by the ends of this puzzle's four longest answers
Final (and a word that can precede the first word of this puzzle's longest answers)
Discussion group, and a word that can follow the ends of this puzzle's five longest answers
Feature of this puzzle's theme answers?
Number of times the letter 'U' appears in each of this puzzle's eight longest answers
Wee hr., and a hint to a feature common to this puzzle's four longest answers
Driveway stuff (and word that's hidden in this puzzle's four longest answers)
Number of protons by which the elements in the four longest puzzle answers have been enhanced
Word that can follow the starts of this puzzle's five longest answers
European acme, and word hiding in this puzzle's 5 longest answers
Zamboni-prepared surface, and word that can follow the last word of the puzzle's four longest answers
Important trial figure, or what you'll be when you read this puzzle's other four longest answers