Sensing, at the quantum level

In our classical world, our eyes and cameras can identify objects once a threshold of intensity has been passed. From this, we identify an image. At the quantum level, not only can we identify single photons emitted from a source, which enables us to visualise just about any object in direct line of sight, but photons of different wavelengths pass are often transmissible through some materials, meaning, we can either see objects through them, or even... around corners (from reflected photons)!