Who is burried in Grant's Tomb? Remember that question? The answer is simple, and yet not really.
Of course Ulysses S. Grant is in there (not burried - more later). Along side General Grant is his wife Julia Dent, who passed away 5 years after the former President. The mausoleum is the largest in the United States and quite a memorial to the General who led us through the Civil War and later became President.
The tomb is actually a National Memorial and while not the largest memorial (Mount Rushmore is much larger, for example), it is the largest mausoleum, modeled after the Mausoleum at Halicarnassus, one of the 7 Wonders of the Ancient World. And General Grant is not technically burried, his remain lie within the Mosoleum itself above ground, not under it.
The tomb is, however, worth a visit. As a National Memorial, Grant's Tomb has a visitors center and guided tours are available. Google Map of General Grant's Tomb, located North of Manhattan on the East side of the Hudson River at Riverside Park. The National Park Service maintains a National Park Service Site of General Grant's Tomb, which includes teacher resources and lesson plans.