What are the biggest marathons?
There are hundreds of marathons around the globe every year.  Only 6 marathons are designated as the major marathons.  Those include the Tokyo Marathon, Boston Marathon, London Marathon, Berlin Marathon, Chicago Marathon and New York City Marathon.
<START_INST>What are the biggest marathons?<END_INST><START_CTX><END_CTX><START_A>There are hundreds of marathons around the globe every year.  Only 6 marathons are designated as the major marathons.  Those include the Tokyo Marathon, Boston Marathon, London Marathon, Berlin Marathon, Chicago Marathon and New York City Marathon.<END_A>