Crack open your wallet, pull out everyone’s favorite portrait of George Washington, and be prepared to learn about some odd symbolism that probably seemed perfectly normal in the 18th century. Here are the explanations behind some of the more baffling parts of our nation’s smallest bills.
What’s that weird pyramid drawing on the reverse of the bill?
The two circular drawings on the reverse of the bill are actually parts of the two-sided Great Seal of the United States. Although we don’t see the entire seal outside of our wallets too often, the notion of having a great seal is actually as old as the country itself. The Continental Congress passed a resolution on July 4, 1776, to create a committee to design a great seal for the fledgling nation, and heavy hitters John Adams, Benjamin Franklin, and Thomas Jefferson got the first crack at creating the seal.
Congress wasn’t so keen on the design these big names brought back, though, and it took nearly six years and several drafts to finally find a suitable seal. Congress finally approved of a design on June 20, 1782.
What’s the story behind the Great Seal of the United States?
According to the State Department, which has been the official trustee of the seal since 1789, both the obverse (front) and reverse (back) of the seal are rich with symbolism. The obverse picturing the eagle is a bit easier to explain. The bird holds 13 arrows to show the nation’s strength in war, but it also grasps an olive branch with 13 leaves and 13 olives that symbolize the importance of peace. (The recurring number 13, which also appears in the stripes on the eagle’s shield and the constellation of stars over its head, is a nod to the original 13 states.) The shield floats unsupported over the eagle as a reminder that Americans should rely on their own virtue and strength.
The symbolism of the pyramid on the seal’s reverse is trickier. The pyramid has 13 steps – the designers apparently never got tired of the 13 motif – and the Roman numeral for 1776 is emblazoned across the bottom. The all-seeing Eye of Providence at the top of the pyramid symbolizes the divine help the early Americans needed in establishing the new country. The pyramid itself symbolizes strength and durability.
The divine overtones don’t stop with the unblinking eye, though. The Latin motto Annuit Ceptis appears over the pyramid; it translates into “He [God] has favored our undertaking.” The scroll underneath the pyramid reads Novus Ordo Seclorum, or “A new order of the ages,” which was meant to signify the dawn of the new American era.
How did the seal end up on our dollar bill?
We can thank former Secretary of State Cordell Hull’s busy schedule for that one. Secretary of Agriculture Henry A. Wallace had to wait for a meeting with Hull in 1934 and decided to kill time by thumbing through a State Department pamphlet on the Great Seal. The pamphlet contained an illustration of the reverse side of the seal with the pyramid, and Wallace was quite taken with the drawing. He took the seal to President Franklin Roosevelt and suggested the country mint a coin using the two sides of the seal.
FDR liked the seal, too. (Roosevelt and Wallace were both Masons and loved the all-seeing eye part of the reverse design, which echoed the concept of the Great Architect of the Universe.) He thought the seal should be on the reverse of the dollar bill rather than a coin, but he was worried the mystical imagery would offend Catholics. After Postmaster General James Farley assured FDR he didn’t think his fellow Catholics would have any problem with the design, Roosevelt approved a new dollar bill design that first appeared in 1935.
Did the Founding Fathers swipe any ideas from a magazine?
Possibly. The familiar E Pluribus Unum motto that the eagle holds in its beak underscores the union and togetherness of the 13 colonies. It might also underscore early Americans’ love of periodicals.
According to the State Department, recent historical research has indicated that this Latin motto may have been borrowed from Gentlemen’s Magazine, a London publication that ran from 1732 to 1922.
The magazine was popular in the colonies, and its title page always carried the E Pluribus Unum motto.
Why don’t the dates on the front of the bills change that often?
At the lower right of the portrait on the bill’s obverse you’ll see the word “Series” and a year. You might notice that these don’t change each year the way the numbers on minted coins do. Why not?
According to the Treasury, the series date only changes when there’s a new design for a bill, a new Treasurer of the United States, or a new Secretary of the Treasury. (These are the two officials whose signatures appear on either side of the portrait.) The series year itself changes when the Secretary of the Treasury changes, while a change in the Treasurer of the United States means that the series year remains the same, but a suffix letter gets tacked onto the end of the year.
What are the various other numbers on the obverse of the bill?
The bill’s serial number is the most prominently displayed set of digits on the dollar, but they’re not alone. If you take out a dollar, you’ll notice there are four large numbers in the corners of the bill’s open space. Like the encircled letter to the left of Washington’s portrait, 
these numbers tell which Federal Reserve Bank issued the note. (Each Fed’s number corresponds the letter of the alphabet assigned to the bank, with A=1, B=2, and so on.)
The tiny letters and numbers that appear on the top left and bottom right of the bill’s obverse indicate the position of the note on the Treasury’s printing plates. If your dollar bill has a tiny “FW” before this code, those letters indicate that it was printed at the Treasury’s facility in Fort Worth, Texas, rather than in Washington, D.C.
Black holes are an object of research and mystery for the whole scientific community from decades. Many researchers are working day and night to explore the mysteries of black holes. In this series, a 
