Described herein are flexible implantable occluding devices that can, for example, navigate the tortuous vessels of the neurovasculature. The occluding devices can also conform to the shape of the tortuous vessels of the vasculature. In some embodiments, the occluding devices can direct blood flow within a vessel away from an aneurysm or limit blood flow to the aneurysm. Some embodiments describe methods and apparatus for adjusting, along a length of the device, the porosity of the occluding device. In some embodiments, the occluding devices allows adequate blood flow to be provided to adjacent structures such that those structures, whether they are branch vessels or oxygen-demanding tissues, are not deprived of the necessary blood flow.