We heard and learned from that https://mathoverflow.net/questions/264330/not-all-manifolds-can-be-triangulated-in-which-dimensions. "All orientable 5-dimensional manifolds are triangulable. In dimensions at least 6, though, you can use their construction to produce non-triangulable orientable manifolds." What are some examples of non-triangulable manifolds which are orientable and non-orientable? >- Oreintable of non-triangulable manifolds, criteria and examples? > - Non-Oreintable of non-triangulable manifolds, criteria and examples? ---- >- 4-dimensional E$_8$-manifold is non-triangulable. But it is a spin manifold. Is E$_8$-manifold triangulable or not? Why and how to prove this?