We weren’t the only ones remembering. William World News had a happy birthday post, and Rick Snider wrote a 50th birthday column.

Still, because I’m a mega nerd, I was inspired to go back and read coverage from the actual opening of the District of Columbia Stadium a half-century ago. In which I learned the following bullet-pointed items.

* The last of 50,000 seats was put in place at 7:10 the night before the place opened, or about 19 hours before kickoff against the Giants. The rushed schedule, The Post reported, “was too much for Mother Nature and to get the desired bright green look on the turf they had to hoke it up a bit. A tank trunk sprayed the sod with vegetable dye shortly before sunset.” Other work was done after nightfall.

* The halftime and in-game entertainment for the first football game at RFK, which also celebrated the Redskins’ Silver Anniversary in Washington, included an almost-doubled Redskins band, a group of percussion dancers called “The Beauty Dots,” and a specialty dance act called “Groggy & Ruth.”

* The stadium had something called a “Tarp-O-Matic” in case of bad weather.

* The stadium’s price tag was listed at $24 million, and as many as 800 men at a time worked on the project.

* While the presidential mezzanine box, designed for JFK’s “unscheduled appearances at games,” was initially planned for the 10-yard line, it was moved to the 40 at the White House’s suggestion “so the projected helicopter pad outside the stadium” would be more accessible.

* George Marshall installed “eight plush red velvet theater-type seats” in the first row of his mezzanine box, the only such seats in the stadium. He also had “a cooler filled with soda pop.” And his cuffs were “turned up in the manner of a teenager.”

* The New York Times described the stadium as “resplendent,” and said the 36,767 crowd at the opener was the largest for a sporting event in D.C. history. The Post said the stadium was “America’s most plush sports palace” and that fans “must have felt they were the affluent society.” The Post also reported that the stadium had 20,521 season-tickets sold.

* The Post also reported that the place was empty 15 minutes after the game ended, that “you could just about set your pace because of the generous width of the gently sloping ramps” and that “a half hour after the final gun, the motorists were just about clear of the parking lots and were being funneled on to relatively free-flowing traffic routes.” Hahahahaha. Also, parking cost $1.

* The quarterbacks at that first game were Norm Snead and Y.A. Tittle. Pat Summerall also played. Also, The Post was still calling Snead “Norman.”

* The Redskins had a 21-7 first-quarter lead, but lost to the Giants, 24-21. “No excuses, no alibis,” Coach Bill McPeak said. “We had the game in our hip pocket and blew it.”

* Opening day glitches included no water in some water fountains and warm water in others, due to a damage to pipes under the field in the rush to finish the work. There was also a mechanical accident cutting off power to the concession stands, which meant the hot dogs were cooked in commisaries, which meant they were “less than tepid.”

* There were also several protests outside the stadium. Desegregationists picketed the team because of its racial policies, while two other groups — the American Nazi storm troopers and the Fighting American Nationalists — were picketing the picketers. “I don’t think anybody’s mad at the players,” the head of the NAACP said. “We know they’d be glad to have Negro teammates. It’s purely the policy of Mr. Marshall that we oppose.”

* The D.C. transit system had planned on busing 3,825 fans to the game, but was surprised by a crush of “about 7500 persons, many of them tightly packed standees.” Some of the buses ended up arriving late to the game. The system’s director promised this wouldn’t happen again.

* Among the tips The Post offered patrons on the day of the game, “Watch where you’re going, in car and afoot” and “Ladies wear loose skirts because some steps are high.”