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Hello and welcome to the documentary from the BBC World Service.
I'm Hannah Gelbart and I'm the host of What in the World,
your daily podcast for the stories that get people talking.
You can listen by searching for BBC What in the World wherever you found this podcast.
Today, we're talking about the past.
Memory is a pretty powerful thing and we tend to look back on our firsts with fondness.
Our first phone.
Our first best friend.
Our first kiss.
More on my first kiss later.
But it turns out you can also feel nostalgic for things that you weren't around for.
So what is nostalgia?
Nostalgia.
That's sentimental feeling of the past.
I get it from looking through old photos or getting out my old iPod or CD player,
or even just sitting down and watching the same rerun of a TV show that I used to love.
But here's something interesting.
Gen Z seems to be especially nostalgic for things that they never experienced.
There's been an explosion of interest in Y2K fashion that looked from the early noughties,