I WONDER - How Are Echoes Caused?

The video explains how sound waves interact with different surfaces. Sound waves can reflect off flat surfaces, creating echoes, or be absorbed by soft materials, making environments quieter. It highlights unique echo phenomena worldwide, including the Cookham Pyramid in Mexico, where a clap echoes back as a bird chirp.

How do sound waves behave differently when they encounter soft surfaces compared to hard surfaces?

What sound does the echo at the Cookham Pyramid resemble?