Histography
histography.io
Interactive timeline of all recorded history from the Big Bang to 2015, drawing from Wikipedia to visualize the density of events by time period and category.
Why it is useful
Histography makes the uneven distribution of recorded history visually striking — the compression of pre-modern time and the explosion of 20th century events is immediately apparent. Clicking any dot opens the Wikipedia article, turning a visual overview into a research entry point.