The presidential inauguration is steeped in history, pageantry and tradition, much of which occurred by accident.
Take the first inauguration. When George Washington took the first oath of office in 1789, he delivered his own address and ended with, "So help me God."
Nothing in the Constitution or statute requires the president to invoke God or give a speech, but every president-elect has done so since, perhaps reasoning that it's best not to mess with certain traditions.
On the other hand, not everything Washington did at his two inaugurals has stood the test of time. For example, at his second inauguration in 1793, he delivered a speech of just 135 words. Not surprisingly, no president since has come close to matching Washington´s brevity.
Other traditions have clung over the years like barnacles to a ship, and proven just as difficult to detach. In 1933, President Franklin D. Roosevelt attended a church service before his swearing-in, and the die was cast. Instead of going to church after the inaugural or the next day, presidents-elect suddenly began sitting in pews the morning of their inauguration.
After the service, the president-elect, the vice-president elect and their families are escorted to the White House by members of the Joint Congressional Committee on Inaugural Ceremonies, which is charged with running the day's events and helps decide which traditions to maintain and which to discard.
"Today, the presidential procession to the Capitol for the swearing-in ceremony follows a firmly established protocol, based on the evolving traditions of past inaugurations," according to the inaugural committee.
The president-elect and outgoing president ride together to the inauguration ceremony, a tradition that began in 1837 with President-elect Martin Van Buren and outgoing President Andrew Jackson. The incoming vice president and departing vice president and their families follow.
One of the few exceptions was outgoing President Andrew Johnson, who had survived an impeachment trial the previous year and refused to accompany the president-elect, Ulysses S. Grant, to his 1869 inauguration. Johnson instead stayed at the White House and signed legislation.
The new vice president now takes the oath of office prior to the president at the inauguration ceremony, a tradition that began in 1937. Prior to that, vice presidents were sworn in inside the Capitol at the Senate chamber and apart from the president.
Presidents traditionally were sworn in on March 4, a practice that changed with the passage of the 20th Amendment to the Constitution in 1933. Now presidents are inaugurated Jan. 20, and if the date falls on a Sunday, presidents take the oath privately that day and then again in a public ceremony the following day.
The tradition of holding the inaugural ceremony outdoors began with President James Monroe, whose ceremony was moved outside after House Speaker Henry Clay refused to allow senators to bring in their own, more comfortable chairs into the House chamber, according to Senate historian Beth Hahn.
Jackson began the tradition of holding the inauguration on the East Front of the Capitol, a practice that ran for 35 inaugurals, interrupted only in instances of foul weather.
The ceremony moved to the West Front of the Capitol with President Ronald Reagan's first inauguration in 1981. The move allowed more spectators to attend the swearing-in and afforded better views. All successive presidents-elect have been sworn in on the West Front.
Mr. Reagan also holds the distinction of having the warmest Inauguration Day on record - a pleasant 55 degrees at his first swearing-in in 1981 - and the coldest one, a frigid 7 degrees in 1985, which forced the ceremony indoors to the Capitol Rotunda.
Like Washington before them, all presidents have delivered an inaugural address. These speeches have been broadcast since 1925, when a national radio audience listened to President Calvin Coolidge's address, and televised since President Harry S. Truman's address in 1949. President Bill Clinton was the first to have his speech broadcast live on the Internet in 1997.
After the inaugural, the outgoing president departs the Capitol to resume his private life, a tradition that began with President Theodore Roosevelt, who went to Union Station and took a train home to New York after congratulating the new president, William Howard Taft.
Outgoing presidents Truman, Dwight D. Eisenhower, and Lyndon B. Johnson left for home by car. Since then, the former president's departure has involved a good deal more pomp and circumstance.
"In recent years, the newly installed president and vice president have escorted their predecessors out of the Capitol after the swearing-in ceremony," according to the inaugural committee. "The members of the Joint Congressional Committee on Inaugural Ceremonies gather on the stairs on the East Front of the Capitol. The new vice president escorts the outgoing vice president and his spouse out of the Capitol through a military cordon. Then, the new president escorts the outgoing president and his spouse through the military cordon."
President Gerald R. Ford embellished the tradition when he and his wife, Betty, left by means of military helicopter, a practice used by every departing president since, weather permitting.
The heavy lifting of the inauguration thus completed, the newly sworn-in president and vice president attend a luncheon sponsored by the inaugural committee. Afterward, tradition calls for the president, vice president and their families to make their way down Pennsylvania Avenue to the White House for the inaugural parade.
In 1873, Grant began the tradition of reviewing the parade from the White House. President Warren G. Harding became the first to ride in the parade in 1921, and President Jimmy Carter broke with precedent by walking in the parade with wife Rosalynn and daughter Amy in 1977, a practice that failed to catch on with his successors.
In 1809, first lady Dolley Madison started the tradition of holding an inaugural ball the night of the swearing-in. The location and number of balls have varied, and they almost died out with the election of President Woodrow Wilson, who nixed the inaugural ball, calling it frivolous and unnecessary.
Harding followed his example by holding a private party instead of a ball. The next three presidents held simpler charity balls, and it looked as though the inaugural ball might fade into extinction until it was rescued in 1949 by Truman.
Thus revived, the balls increased in number before reaching a high of 14, with the 1997 inauguration of Mr. Clinton. The most recent inauguration, that of President George W. Bush in 2005, saw nine balls.