CHIVA, Spain (AP) — Irene Cuevas will never forget the sound of the waves crashing below her apartment’s balcony. If only there had been a flash of lightning in the darkness to let her glimpse ...

There are eight sounds to choose from which allows you to experiment and find which one works best: Waves, birdsong, rain, car journey, spaceship, white noise, pink noise and brown noise.

The process is very similar to ultrasound imaging. However, the sound waves used are within normal hearing range, and they are used to identify objects rather than internal structures. This ...