I think technically the mode is one of the middle buckets, it looks slightly taller to me. Anyways, it's a histogram, so the x-axis is split into buckets. The

I think technically the mode is one of the middle buckets, it looks slightly taller to me. Anyways, it's a histogram, so the x-axis is split into buckets. The bar all the way on the left is likely some range of hours from 0 to whatever the bucket size is