A multifunction device displays a navigation user interface that includes: a navigation bar having a plurality of unit regions and a plurality of subunit regions. Each of the unit regions represents a range of values. Each subunit region represents a subset of a respective range of values. The navigation user interface also includes a content area for displaying content associated with subunit regions. In response to detecting an input that selects a respective subunit region, the multifunction device updates the content area in accordance with the respective selected subunit region. In response to detecting an input that selects a respective unit region, the multifunction device updates the navigation bar to include subunit regions in accordance with the selected unit region and updates the content area in accordance with at least one of the subunit regions in the updated navigation bar.