December 22 is Mathematics Day in India. It was declared in 2012 commemorate the 125th birthday of Srinivasa Ramanujan, the legendary mathematician from India. Ramanujan was born December 22, 1887, and there are any number of remarkable-but-true stories about him. He didn’t have any formal training in math, and took a completely novel approach to many mathematical areas and problems. None of the more local mathematics professors could be bothered with his work, but when he corresponded with a professor at the University of Cambridge in England, G. H. Hardy, who did recognize his abilities and put together plans for Ramanujan to visit him in Cambridge.

After Ramanujan’s initial letter, which contained samples of his theorems, Hardy said it was “certainly the most remarkable I have received”. Ramanujan, he continued, was “a mathematician of the highest quality, a man of altogether exceptional originality and power.” He tried to convince Ramanujan to visit Cambridge, but Ramanujan declined. However, thanks to the interest of Hardy and his colleagues, Ramanujan received a fellowship to the University of Madras. At some point during the following year, Ramanujan apparently changed his mind and accepted the invitation to visit England. He spent several years there, producing more work that continued to astonish leading mathematicians. He was elected to both the London Mathematical Society and became a Fellow of the Royal Society — one of the youngest ever. Ramanujan is the subject of The Man Who Loved Numbers, the 2015 PBS documentary The Man Who Knew Infinity, Ramanujan, a 2014 biographical film, and several other films, stage productions, and books, and mathematicians agree that his work continues to heavily influence the field.

There’s probably more math in use in modern times than in all — or at least most — of history. For one thing, now we have engineering projects like the fastest airplane in history, the Lockheed SR-71 Blackbird. Nobody has ever said whether the SR-71 engineering team were admirers of Ramanujan, but the very first flight of the airplane was on his birthday, December 22, 1964. The plane started setting speed records almost immediately — and most of them haven’t been broken. But speed in the sky and speed on a road are two different things; December 22 was also the day, in 1965, the United Kingdom instituted the first uniform 70mph speed limit on all roads and motorways.

The US hasn’t always welcomed world commerce.

Sometimes speed rules don’t just mean an upper limit, but a minimum as well. That’s been the case in New York’s Lincoln Tunnel ever since it opened — on December 22, 1937. The minimum speed, by the way, is 20mph. Because it offered the most direct route from New Jersey to downtown Manhattan, the tunnel was busy right from its opening; 3,700 vehicles used it in its first 12 hours. Although the largest trucks weren’t allowed through at first, the tunnel provided a major boost to commerce, opening more traffic carrying people and goods to and from the Port of New York, and from there throughout the world.

But the US hasn’t always welcomed world commerce. On December 22, 1807, the US Congress passed the Embargo Act, which effectively banned trade…with all foreign nations. It wasn’t really about trade, though. The Napoleonic Wars were being fought in Europe, and the British Navy had begun intercepting American ships — not for the cargo, but to “impress” crew members into service on British naval vessels. Besides that, when an American ship sailed to Europe, its cargo might be seized by the French (if it was headed for England or its allies) or by the British (if it was headed for France or its allies). The US President at the time was Thomas Jefferson, and while he realized that the new nation didn’t have a military that could rival any of the established European powers, he thought the US would have some leverage from “commercial warfare”.

In a word, it didn’t work. The only economy that got damaged was the US itself, and far from improving its diplomatic and commercial leverage, the outcome was that European traders simply found alternative sources of whatever they’d been buying from the US. Jefferson’s political party lost a significant proportion of its power the next year, and in 1809, just before his term ended, Jefferson signed a new law nullifying the Embargo Act, and making it possible to reopen trade with England and the other European nations. In another word, that didn’t work either. The relationship between the US and England continued to deteriorate, and not too much later the War of 1812 began.

But eventually trade resumed, pretty much to the satisfaction of everybody. The opening of things, from trade to tunnels to railways (the Cornwallis Valley Railroad in Nova Scotia opened on December 22, 1890) seems to give people hope that improvements are on the way. Even a reopening can have that effect. Sentiments were definitely hopeful on December 22, 1989 when the Brandenburg Gate reopened in Berlin, Germany after decades of Cold War-related closure. An opening or reopening just feels like a step in the right direction, and you have to take things step by step. You know, like that song One Step at a Time from Jordin Sparks’ platinum-selling debut album. Funny thing, though. Do you know when Jordin Sparks was born? On December 22, 1989, the very day the Brandenburg Gate reopened.