I'll sell you up to 50,000,000 acres on Mars for 1/5,000,000th of a bitcoin each, lmk if you want me to send a btc address. Proof of ownership will be provided as a convenient and portable .txt file

If you but the whole amount, I'll write into my will that my decendant's also have to honor your claim. If any of them becomes king or queen of mars, could be quite lucrative!