no trust me im a time traveler
if they year is prior to 1914 then there will be a world war spanning 1914-1918
in 1929 the US stock market will crash, causing the largest economic depression in history
in 1933 a man by the name Adolf Hitler will become chancellor of Germany, putting anti semetic laws in place and ending german democracy for a while
in 1939, a second world war will begin with a joint soviet-german invasion of poland
in 1945 that war will end with a new weapon of mass destruction, the nuclear bomb, being detonated over hiroshima then nagasaki
in 1969 the USA will land people on the moon
in1991 the soviet union will collapse
in 2014 russia will annex crimea from ukraine
in 2021/2, russia will begin an invasion of ukraine that is ongoing to 2025