Tallinn TV Tower

You're standing at the Tallinn TV Tower, the tallest structure in Estonia. Go on, look up. It's over three hundred metres tall: a concrete shaft of a hundred and ninety metres, topped by a steel mast of a hundred and twenty-four. See the rings in the concrete? They come every two and a half metres. The builders poured concrete non-stop for eight months, into a mould that kept sliding up and getting narrower. That's how the tower rose above the landscape, ring by ring.