This visualization displays US recession periods from 1854 to 2021 as a sequence of bars, where blue bars indicate recession years and the y-axis shows recession status (0 or 1). Users step forward or backward through time using "Next Year" and "Previous Year" buttons, which dynamically append or remove data points. The implementation uses D3 v7 with SVG rendering, employing d3.scaleBand for the x-axis, d3.scaleLinear for the y-axis, and the general update pattern with transitions that slide new orange bars into place before recoloring them blue.