Explore the fundamentals of geometry and topology in this comprehensive lecture from the International Centre for Theoretical Sciences' workshop for university lecturers. Delve into the study of surfaces in R3, examining polyhedrons, Platonic solids, and regular solids. Learn about the Euler number and its application to regular solids, and engage with practical exercises to reinforce your understanding. Discover how to construct boxes using triangles and investigate more complex polyhedrons. The lecture culminates with an introduction to the Gauss-Bonnet theorem, providing a foundation for further exploration in this active field of research. Gain valuable insights through the included Q&A session, designed to clarify concepts and promote deeper comprehension of geometric and topological principles.