Then and Now (Gothamist)
When the World's Fair opened 50 years ago today, the skies were rainy and protesters threatened to obstruct the festivities. Reportedly many were scared off not just by the weather and demonstrators ("Civil Rights proponents hope to stage a variety of dramatic protests inside the World's Fair at the opening"), but by a threat to pull emergency cords on subways, which was part of the "stall-in" plan:

(Gothamist)
The NY Times reported on April 23rd, 1964: "An attendance of at least 250,000 had been forecast," however, "attendance was 92,646, with 63,791 paid."

Even if critics thought it wasn't as good as Brussels in 1958, eventually attendance did pick up, and over time even the frail, crumbling site of the World's Fair has remained a popular, albeit deteriorating, destination for some. So much so that today, the 50th anniversary, drew massive crowds to the site, as the New York State Pavilion was opened to the public for the first time in 27 years. Check it out:
According to NextCity, by 11 a.m. "the line had crossed the Grand Central Parkway, with a minimum wait time of at least three hours, according to a Parks Department worker on site. Every parking lot near the site was jammed, and officials were trying to direct a massive snake of traffic through the park’s one-lane streets, with limited success. Robert Moses is creating congestion from beyond the grave."

(Gothamist)
What did today's visitors see? We were there, and will have more on our visit soon.