As you know, Chinese is a great language, not just for its long history but also for its one character sharing many pronunciations and meanings. Look， “堡” is a good example.
When 堡 is pronounced as pù, it refers to a courier station. It was used to serve the ancient officials to take a rest during their tour, or change for horses for those who sent the imperial edicts, but now it can be a name of a village. So we have五里堡（wǔ lǐ pù）, 十里铺（shí lǐ pù）, 二十里铺（èr shí lǐ pù）.
When “堡”is read as bǎo , it means to be a fortress, an earthwork town or defence works. So we say 堡垒（bǎo lěi）.
If someone says he is from a bǔ , his meaning is that he was born in a walled town. For example, 瓦窑堡（wǎ yáo bǔ）
This time it can be something that are not easy to sort out, 科学堡垒
(kē xué bǎo lěi),for instance.
You see, next time be careful when you meet the Chinese character “堡”.
（Finally I should say many thanks to Mr. Hu Xiaochen in Yu County who helped me take some of the pictures above.）