  Spin-triplet superconductors are novel materials capable of harboring
Majorana bound states that can be used in topological quantum computing.
However, such bulk materials are still rare. Here we review the results that
established K2Cr3As3 as a spin-triplet superconductor with transition
temperature T_c as high as 6.5 K. We focus on the multiple-phases feature, and
its exquisite distance to a ferromagnetic quantum critical point which is
likely responsible for the high T_c. We touch on the topological aspect of the
superconducting state, and suggest that it is a new route to the technical
implementation using a topological spin-triplet superconductor at the highest
temperature ever.
