The Robert E. Lee is the second largest Sequoia in the Grant Grove (home of "America's christmas tree") in Kings Canyon NP. It is the twelfth largest Sequoia (and by extension the twelfth largest living thing) known.
The fallen trunk on the right is the remnants of a tree known as the fallen Monarch.
Here's the view of Robert E. Lee from its base. This image was taken having walked through the fire-hollowed trunk of the Fallen Monarch. Robert E. Lee stands 254 feet tall with a trunk 22 feet in diameter. Although both these stats suggest it is smaller than the California tree it is actually bulkier.