Eternal Mana Rift

At the beginning of your upkeep if you control no
other legendary permanents, sacrifice Eternal Mana
Rift.
{w}{w}{t} Add {w} for each planes you control.
{u}{u}{t} Add {u} for each island you control.
{b}{b}{t} Add {b} for each swamp you control.
{r}{r}{t} Add {r} for each mountain you control.
{g}{g}{t} Add {g} for each forest you control.
And they thought mana could be sealed away, Oh how
wrong they were when the seal burst immediately.