Heiden

"People really need an early warning in order to determine what to do," says Paul Heiden, chief executive of Optics11, a Dutch firm that also makes fibre optic acoustic sensing systems.

Mr Heiden argues that cables installed solely for the purpose of monitoring marine activity could be especially useful – one might place such listening cables, say, 100km from a vital port, or in the vicinity of a key gas pipeline or telecommunications cable, rather than within those assets themselves.

Optics11's fibre optic listening technology can be deployed on military submarines, Mr Heiden adds, and he says the firm is soon to begin testing a monitoring cable installed somewhere on the floor of the Baltic Sea.

Heiden had more to contribute, saying that instead of a bucket list, she has a forget-about-it list.

She wound up in a Jewish boarding school in the picturesque village of Heiden that, because of the Holocaust, essentially became an orphanage.