Here you can download free data of the S&P 500 from 1789 until today (for Excel, in format: Daily, Weekly, Monthly, etc.):
hxxps://stooq.com/q/d/?s=%255Espx&c=0
translation of the small window:
Zarzadzaj opcjami = Manage options
Zgadzam sie = I agree
write at the top left (in the box: Symbol np): ^SPX and then click on: Kwotuj
check that in the bottom left-hand corner the following is selected: Historical data
choose Interval: Daily, Weekly, Monthly, etc...
click at the bottom on: Download data in csv file
Before you click on the button: Download data in csv file,
you should click on: semicolon (at the bottom, where it says: Downloaded data separator: comma | semicolon) so you get the file: csv with the columns already separated: Date, Open, High, etc...;
then, to quickly transform the csv file to Excel file (xls or xlsx), you can use this free service:
hxxps://convertio.co/it/csv-xls/
hxxps://convertio.co/it/csv-xlsx/
hxxps://i.postimg.cc/hPNyKdSD/S-P-storico.jpg
You can get the Indexes of the whole World (also Commodities, Metals, etc...), by writing in the box: Symbol np
DJI (Down Jones Industrial)
Nasdaq
FTSE (United Kingdom)
DAX (Germany)
Nikkei (Japan)
Nifty (India)
IDX (Indonesia)
FTSE MIB (Italy)
etc...
Cotton, Soybean, Silver, Gold, etc....