  In this paper we show that flat (m-1)-dimensional tori give nontrivial
rational homology cycles in congruence covers of the locally symmetric space
SL(m,Z) \SL(m,R)/SO(m). We also show that the dimension of the subspace of
H_{m-1}(\Gamma \SL(m,R)/SO(m);Q) spanned by flat (m-1)-tori grows as one goes
up in congruence covers.
