What modern structures serve as the same purpose as watch towers along the great wall of china?

The watchtowers were built along the Great Wall. The total number of towers was about 25,000 and the distance between each tower differed.

Some of them were very close to each other at a distance of about 3 miles, while some of them were far away from each other at a distance of several miles.

Watchtower Functions - Signal Alarm (communication), Storage (food and weapons), and Living Quarters (for the soldiers)

Many modern structures serve the same purpose today