How to access all xlsx files in all subdirectories?

[Krszt]

Hello,
How to modify this program if I have more dirs in dir1 to get all xlsx.?
So the xls files are within different dirs in dir1, like
dir1\1990\1.xlsx
dir1\1991\123.xlsx
dir1\1992\124.xlsx

    import glob
    from win32com.client import Dispatch
    
    
    for file in glob.glob('C:\Users\igyulavics\Desktop\dir1\*.xlsx'):
        xl = Dispatch('Excel.Application')
        wb = xl.Workbooks.Add(file)
        wb.SaveAs(file[:-1], FileFormat=56)
        xl.Quit()