In this is 99%

in the 17th century.

If you're listening with someone who may not be ready for that, you might want to preview it first.

This is 99% invisible.

I'm Roman Mars.

Take a walk through Central London and one building is particularly hard to miss.

Just off the banks of the River Thames, the shard is Western Europe's tallest skyscraper.

At just over 1,000 feet high, the building's slender tapering design doesn't so much stretch

into the sky as it pierces through it.

11,000 panes of glass make up the facades which all slope gently inward, rising towards

the top so that the building comes nearly to a point.

Thousands and thousands of people walk past the shard every day, but there's only a select few

who look up at it and breathe a sigh of relief.

I just kind of wipe the sweat from my forehead going,

you know, yes, oh, thank goodness that's still there and still standing.

This is Roma Agruwal, one of the structural engineers behind the shard.

Her job is to make sure buildings, bridges, and all sorts of other things

withstand the test of time. As a structural engineer, Roma looks at the built world with a special kind of x-ray vision.

So I might consider what the skeleton of the main structure might be, you know, what material

is it made from, where do the main bones of it sit and so on, and I also might think

what's underground, you know, what's actually holding this thing up, how deep does this thing go.

So I'm trying to look beyond the visible.

...