English

Flatland: A Romance of Many Dimensions
http://www.alcyone.com/max/lit/flatland/index.html
Online resource of Edwin A. Abbott's classic tale of interdimensional experience.
Subjects:   Geometry & Trigonometry  

Geometry from Mathworld
http://mathworld.wolfram.com/topics/Geometry.html
This site is a comprehensive and interactive mathematics encyclopedia intended for students, educators, math enthusiasts, and researchers.
Subjects:   Geometry & Trigonometry