Dzhokhar Tsarnaev, Surviving Boston Bombing Suspect, Has Been Arrested

[Update: There has been a confirmed bombing at the finish line of the Boston Marathon with multiple dead and injured reported. Review this live blog for the latest information.]

The 117th Boston Marathon is today, with 27,000 runners expected to start the race. Today's temperatures are expected to be in the low to mid 50s, unlike last year when temps hit 80 degrees. Kenyans have dominated the marathon over the last two decades, especially on the men's side, where a Kenyan has won 19 out of the last 22 marathons. However, Ethiopian Gebre Gebremariam is a favorite. On the women's side, Kenyan Sharon Cherop will try to defend her title against a field that includes local hopeful Shalane Flanagan from Marblehead, Mass.