pyramids用英语描述简单，清晰点

A pyramid is one of the earliest form of massive monumental architecture built by humans. Pyramids are shaped like big three-dimensional triangles, with larger bases narrowing towards the top; this architectural design is extremely durable, as can be seen by the numerous examples still preserved after thousands of years.

The pyramid is the logical form of architecture if you want to build something to last, and so you can find examples of pyramids in Egyptian, Mayan, and Incan civilizations and possibly China.