The Long Now Foundation chose analog etched metal for a Very Long-Term backup [0]. Although their time scale is more link 10,000 years, much longer than you are

The Long Now Foundation chose analog etched metal for a Very Long-Term backup [0]. Although their time scale is more link 10,000 years, much longer than you are thinking. [0] https://longnow.org/ideas/02008/08/20/very-long-term-backup/ https://longnow.org/ideas/02008/08/20/very-long-term-backup/