centre_year_BC_AD,duration_yr,name
1970,80,Modern
505,50,
305,30,
-245,70,
-435,50,
-2065,50,
-2955,30,
-3170,100,
-3405,50,
-3860,50,
-6120,40,
-6280,40,
-6515,70,
-6710,40,