SEOUL (Reuters) - Covering a North Korean military parade is an emotional rollercoaster. Foreign journalists stand just meters from the action in Pyongyang’s Kim Il Sung Square.

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It is a visual and sensory barrage. Your eyes are assaulted by the technicolor pallet of socialist-realist propaganda. The ground at your feet shakes as tanks rumble past, leaving a diesel aftertaste in your mouth.

That heavy equipment, and the brigades of tightly coordinated goose-stepping soldiers that come before them, are an impressive sight.

But the thousands of North Koreans cheering and crying for hours for leader Kim Jong Un, who watches from a balcony 30 meters behind us, can also be overwhelming. You can see the tiredness in their faces.

The parades offer weapons analysts and U.N. investigators a rare chance to gain new insight into secretive North Korea’s military capabilities. Every nut and bolt in every photo and video is closely scrutinized.

North Korea likely knows this, and sometimes reveals new and untested equipment. It did so on Saturday, displaying what appeared to be two new kinds of intercontinental ballistic missile in its military arsenal.

The second area of interest to North Korea watchers is the balcony where Kim and his aides stand. To whom is Kim talking, with whom does he shake hands first? Is his elusive sister, Kim Yo Jong, up there with him?

She often is, and was on Saturday, lurking somewhere behind a pillar or bright red flag, her mischievous smile a surreal antidote to the militaristic pomp and ceremony of the event below.

On TV, these parades appear as a tightly choreographed and slick affair. But on the ground, it is the little details which slip through that facade that are most interesting.

That perfectly synchronized goose-stepping is aided by thousands of painted white dots placed a meter apart on the ground, guiding boots to the right spot. And behind Kim’s balcony is a large traffic light and countdown clock which gives each platoon the signal to begin marching.

One of the most visually spectacular aspects of the parade is the large human screen behind the center of the action. There, hundreds of thousands of North Koreans hold up colored placards which, viewed from a distance, spell out huge propaganda slogans.

But easily lost in that mass scale are the individual faces of those human pixels who, dressed in their finest clothes, stand holding plastic flowers in the sun for hours.

Divided into work units, people prepare for months for such events, often having no choice but to forgo time at weekends and after work to practise.

This is in addition to the economic double life most North Koreans lead, whereby meager income from official jobs is supplemented on a thriving network of semi-legal markets.

As they walk past Kim Jong Un’s balcony, some people are overcome with emotion and cry. Others look gaunt and exhausted.

When the parade is over, the square hums with activity as the different groups all go their separate ways. The pink petals from their plastic flowers leave a trail behind them.