  Noting that T-duality untwists S^5 to CP^2 x S^1, we construct the duality
chain: n=4 super Yang-Mills --> Type IIB superstring on AdS_5 x S^5 --> Type
IIA superstring on AdS_5 x CP^2 x S^1 --> M-theory on AdS_5 x CP^2 x T^2. This
provides another example of supersymmetry without supersymmetry: on AdS_5 x
CP^2 x S^1, Type IIA supergravity has SU(3) x U(1) x U(1) x U(1) and N=0
supersymmetry but Type IIA string theory has SO(6) and N=8. The missing
superpartners are provided by stringy winding modes. We also discuss IIB
compactifications to AdS_5 with N=4, N=2 and N=0.
