Have we ever had parades like they have in Russia, North Korea, China, etc., where tanks and missiles are paraded in front of a head of state or something? If so, when was the last one, and what was the occasion?
There used to be an "Armed Forces Day" parade in Colorado Springs when I was a little kid in the late 1950's. Featured tanks from nearby Fort Carson, military bands etc. Seems like it was held in May of each year. Maybe it was a local deal - we moved to San Antonio when I was 10 and I never heard of Armed Forces Day again. Guess I'll Google it and see what I find....
The Grand Review of the Armies in 1865 is the closest pure example of what you're asking that I can think of.
It's probably apocryphal, but I always enjoyed the tale of the German baron whom, upon seeing the Army of the Potomac, said, "Why, with such men I could conquer the world!" And when Sherman's men passed, said, "With these men I could conquer Hell, too!"
In 1933 the Roosevelt administration put on the "Parade for Prosperity" as part of its multi-faceted propaganda campaign in support of FDR's attempted fascist takeover of the entire US economy under the 1933 National Industrial Recovery Act (NIRA) and National Recovery Administration (NRA). Over a million people watched the parade as marching bands, soldiers, labor unions (who had a hand in writing the NRA codes), industry-specific trade and business associations (who also had a hand in writing the NRA codes), big business (who also had a hand in writing the NRA codes), government bureaus, and other patriotic-themed participants marched up and down the streets of New York City.
In the video below, if you pay close enough attention, you might even catch a glimpse of the NRA's fascist logo, the Blue Navajo Thunderbird, along with the NRA's theme "We Do Our Part." As part of the larger propaganda campaign, the main point of the parade was to - through a combination of peer pressure, an appeal to Americans' inherent patriotism, and the emotional power of the event itself - convince the American peoples to willingly go along with the government takeover of their economy.
In terms of the scale, symbolism, appeals to patriotism, and overall purpose of the "Parade for Prosperity,"one could almost mistaken it for similar events concurrently taking place overseas in Rome, Nuremberg, and Moscow.
As a footnote to the story in 1935 the Supreme Court ruled the NIRA and NRA unconstitutional. It was the last time in American history that the Supreme Court said "no" to the President and/or Congress on an issue of major significance. Over the next few years, however, FDR would re-implement many of the defunct NIRA and NRA's policies under the guise of the Wagner Act, the WPA, and other post-NRA "alphabet agencies."