|The Zimmerman deal|
100 years ago this month, Germany was losing World War I and was looking for help. Its Foreign Secretary sent a telegram to Mexico, promising the return of Texas, Arizona and New Mexico in return for military support if the USA should enter the War.
Thanks to a cable-cutting competition between the Allies and Germany, the only way for the latter to transmit the message was from London via the first submarine link laid to America, which ran into the sea near the tiny, remote village of Porthcurno, Cornwall.
The line was tapped, and the code was cracked by a Classical scholar genius called De Grey - the Alan Turing of his time, but unassisted by computers. When the telegram was made public and Zimmerman admitted its authenticity, that tipped the balance and America joined the Allies.
The three States promised to Mexico currently have a combined population of 34 million - more than 10% of the USA's total - and a combined GDP of c. $1.75 trillion dollars, which is around 9.6% of the US national turnover. Oil resources include the East Texas Oil Field (originally holding c. 7 billion barrels of oil) and (recently discovered) up to another 20 billion barrels in West Texas.
The proposed Wall between the two nations could have been longer - and who knows which way the people would be trying to cross?
And if you're planning to visit Cornwall:
http://www.porthcurno.org.uk/ [the Telegraph Museum]