Complex sentence: Spokane is home to the Lilac Bloomsday Run, held on the first Sunday of each May, which is a race for walkers, and competitive runners, which is the largest timed road race in the world, typically drawing about 45,000 participants.
Split into simpler sentences: Spokane is home to the Lilac Bloomsday Run, held on the first Sunday of each May, which is a race for walkers, and competitive runners. Today, Bloomsday is the largest timed road race in the world, typically drawing about 45,000 participants.