Each row is one date and each column is one continent, so events from the same year sit side by side. Political and social events appear alongside cultural milestones in art, music, literature, and ideas, tagged "Culture", and with major buildings, palaces, and wonders of the world, tagged "Building". The rows don't follow a linear time scale. Big gaps of time can sit between two neighbouring rows, especially before 1000 BCE. "c." means the date is approximate.