What is the name of the device and how does it function?

Recently I have come across a device at an archaeological monument where in, the tourists / visitors get the history and all other related information of the monument directly into their hand set (Mobile set)
This audio-visual ( Wi-Fi ) device is so powerful that the carvings at the highest point of the doom can be very clearly visualize and at the same time,the history behind the monument can be audible through ear phone.

Can any body from the community give information on following points::--
(1) What is the exact name of this device?
(2) How does it function?
(3) What all components are employed in this device?
(4) Who are the manufacturers?

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