Rainbows over Montana

Somewhere in Montana before we hit the park we saw this double rainbow.  It sparked a great debate over what the end of the rainbow was like.  I hold that there is indeed an end to a rainbow.  I have seen it myself, a rainbow ending in a field.  Mom (aka Grandmom) insists that rainbows don't end, they are a continuous arc in the sky that had no beginning and no end;  rainbows are a circle.  Now, for all you smarty pants out there who want to tell us the truth, we will pass...we are very well aware that we can go onto the internet and find the answer in about 30 seconds.  We prefer to live with our illusions.  What we all agreed on was that it was a real treat to see a double rainbow over Montana.