On January 2nd, 1492, Ferdinand and Isabella took the surrender of Granada, and a 40-year-old sailor from Genoa watched from the crowd. For 6 years Christopher Columbus had asked them to pay for a voyage west to Asia, and twice their experts had told them the ocean was too wide. Within days they turned him down again, this time over his price: admiral, viceroy, and a tenth of the profit. He packed his charts on a mule and rode for France. Back in the camp, the king’s finance officer told the queen the whole fleet needed only 2,500 crowns, about a quarter of 1 percent of what the war had cost, and offered to lend it himself.

She had 2 choices. Let him go, or send someone after him. She sent a court officer, who caught Columbus on a stone bridge 4 miles down the road. The contract was signed April 17th, 3 ships left Palos in August, and on October 12th a lookout sighted land in the Bahamas.

What if she’d let him go?

This week we hit CTRL+Z on the bridge at Pinos, and follow the ripple to today: a Genoese chartmaker growing old in a room over the harbor at Honfleur with Japan drawn 2,400 miles west of the Canaries, a Portuguese clerk writing Lisbon a letter about parrots from a beach in Brazil, a Breton captain named Jacques Cartier anchoring off Hispaniola in 1534, a grandson of Moctezuma ruling a city that buys its matchlocks from Norman traders, and a Spanish army marching out of the Netherlands because the king can’t pay it. In 2026 the 2 continents are called Santa Cruz, Portuguese is spoken from the Amazon to the River Plate, and Tenochtitlan is still on its lake, because one January a queen let a sailor keep riding.