A page of the Numeropedia - the Special Encyclopedia of Numbers
... In Arithmetic, 1+1 = 2, in Computer Science, 1+1 = 0, but in Love, 1+1 = 1!
[Astronomy] The Earth is the only planet in the Solar System, whose name is not after a mythical god.
[Astronomy] Venus is the only planet in the Solar System that rotates clockwise (viewed from its North pole).
[EECS] Nonce is a value used only once within a specified context.
[Geology] Maine is the only U.S. state bordering with only one other state (New Hampshire).
[Geology] Twenty countries having exactly one bordering country: Brunei (by Malaysia), Canada (by U.S.), Cuba (by U.S. Naval Base, Guantanamo Bay), Denmark (by Germany), Dominican Republic (by Haiti), East Timor (by Indonesia), The Gambia (by Senegal), Gibraltar (by Spain), Guadeloupe (by Netherlands Antilles), Haiti (by Dominican Republic), The Holy See/Vatican City (by Italy), Ireland (by United Kingdom), South Korea (by North Korea), Lesotho (by South Africa), Monaco (by France), Papua New Guinea (by Indonesia), Portugal (by Spain), Qatar (by Saudi Arabia), San Marino (by Italy) and United Kingdom (by Ireland).
[Geology] Antarctica is the only continent that has no country. Many countries establish science stations here, but officially own no land.
[Geology] Australia is the only continent having only one country: Australia.
[Geology] The only country whose English name includes the word “name” is Suriname.
[Geology] The only lake in the Five Great Lakes does not border Michigan is Lake Ontario.
Michigan is the only U.S. state that borders 4 lakes in the Five Great Lakes (Lake Erie, Huron, Michigan and Superior), except Lake Ontario.
[Geology] The number of the U.S. state names starting with the compass direction word “West”: West Virginia. East is the only compass direction name that was not used in any U.S. state names. North and South are for both Carolina and Dakota.
[Geology] Delaware, the only U.S. state has no unit of National Park System, such as national parks, seashores, historic sites, battlefields, memorials and monuments.
[Geology] Juneau, Alaska is the only U.S. state capital city accessible only by boat or airplane.
[Flag] The only U.S. state flag that has a pennant design is Ohio.
[Flag] The only U.S. state whose flag has 2 sides is Oregon. A beaver is figured on the back. On the front are “State of Oregon”, a seal and the year “1859”.
[Flag] The national flag of Bosnia and Herzegovina is the only national flag that features stars in half: one top half-star and one bottom half-star (together with 7 full stars).
[Flag] The national flag of Libya is the only national flag that has only one color: plain green, the traditional color of Islam.
[Flag] The national flag of Aruba is the only national flag that features a 4-pointed star.
[Flag] The national flag of Switzerland is the only national flag that is square (red square with a white cross).
[Flag] The national flag of Australia is the only national flag that features 2 types of star, five 7-pointed stars and one 5-pointed star.
[Flag] The national flag of Nepal is the only national flag that is not rectangular (or square); its shape is of 2 overlapping right triangles of different shapes.
[Gov.] Louisiana is the only U.S. state that is administratively divided into (64) parishes, instead of counties.
[Gov.] Alaska is the only U.S. state that is not administratively divided into counties (or parishes, as of Louisiana).
[History] John Fitzgerald Kennedy is the only U.S. president who won the Pulitzer Prize, for his work “Profiles In Courage”.
[History] The only U.S. state having unicameral legislature is Nebraska.
[History] Washington is the only U.S. state named after a U.S. President, George Washington. It has the only U.S. state flag that has the portrait of a U.S. President.
[History] Abraham Lincoln is the only U.S. President receiving a U.S. patent. In 1849, he (then Illinois congressman) received a patent (#6469) for “a device for buoying vessels over shoals” or sand bars.
[History] The Great Pyramid of Giza, Egypt, near the city of Memphis, serving as a tomb for the Egyptian Pharaoh Khufu, is the only one Wonder of the Ancient World still surviving.
[History] The only city in Nevada that gambling is illegal: Boulder City, even though in March 1931, then-governor Fred Balzar signed into law the bill legalizing gambling in Nevada.
[History] The only royal palace in the U.S. is Honolulu’s Iolani Palace.
[Language] The only English word ending with 2 letters “mt” is “dreamt”.
[Language] The only English word having double “ii” is “skiing”, excluding Hawaiian original words.
[Language] The only English word with one vowel (i) occurring 6 times is “indivisibility”.
[Language] The only English word that begins and ends with letters “und” is “underground”.
[Language] The number of syllables in the word “one”, the only number in English that its value is equal to the number of its syllable, 1.
[Language] The only U.S. state name having 4 identical vowels (i) and 4 identical consonants (s): Mississippi.
[Math.] There is exactly one line passing through any 2 points.
There is exactly one circle passing through any 3 non-linear points in the 2-dimension Euclidean plane.
[Sport] Golf is the only sports that scores could be displayed in negative numbers.
[Sport] Colorado, the only U.S. state in history to turn down a chance to host the Olympic [Game] in 1976, planned to be held in Denver.
[Sport] The 1972 Miami Dolphins is still the only NFL (National Football League) team with a single perfect season at win-lose record 17-0 (regular season 14-0 and playoffs 3-0, including winning the Super Bowl VII over Washington Redskins).
[Sport] The 2007 New England Patriots also had a perfect regular season, at 16-0, went up to 18-0 after 2 playoff winnings, but was upset by the New York Giants in the Super Bowl XLII (42).
[Trivia] Iowa is the only U.S. state name starting with 2 vowels: “I” and “O”. Even more interesting, in a French map in 1763, it was spelled as: “Ouaouiatonon”, starting with 7 vowels.
[Trivia] The only English word that is still pronounced the same way when the last 4 letters are removed from the end of it: “queue”.
[Trivia] The only bed aboard the Air Force One is of curse for the U.S. President.
[Trivia] Maine is the only U.S. state name having only one syllable. [Trivia] Utah is the only U.S. state whose capital’s name is consisting of 3 words: Salt Lake City; even more specially, each word has 4 letters. [Trivia] The only country name (English) stating with letter O is Oman. The only country name (English) starting with letter Q is Qatar. The only letter that does not start any country name (English) is X. [Trivia] Letter A is the only English vowel that is not on the same row with other vowels in the English language keyboard.
[Trivia] Maine is the only U.S. state name having only one syllable.
[Trivia] Utah is the only U.S. state whose capital’s name is consisting of 3 words: Salt Lake City; even more specially, each word has 4 letters.
[Trivia] The only country name (English) stating with letter O is Oman.
The only country name (English) starting with letter Q is Qatar.
The only letter that does not start any country name (English) is X.
[Trivia] Letter A is the only English vowel that is not on the same row with other vowels in the English language keyboard.
[Zip] The only U.S. town having the 2 U.S. Postal Zip Codes starting with 00: Holtsville, New York 00501 and 00544.