Philadelphia Inquirer/Rapport Press

HANDOFF: Barack Obama was sworn in Tuesday as the nation’s 44th president. More than one million people gathered for the event.With Mr. Obama’s first day on the job scarcely begun, the financial uncertainty facing his presidency made itself felt. The Dow Jones Industrial Average fell 4%, its worst inauguration-day performance in history, amid fresh signs of trouble among the nation’s banks.

WASHINGTON — On a day rich in history, Barack Obama took office Tuesday as the 44th president of the U.S., urging Americans to stand together amid the “gathering clouds and raging storms” of war and recession.

The inauguration of the first African-American to lead the world’s most powerful country drew a crowd of well over one million to the National Mall here. In his 18-minute address, Mr. Obama called on Americans to return to the values of “hard work and honesty, courage and fair play, tolerance and curiosity” that have seen the country through past crises.

With Mr. Obama’s first day on the job scarcely begun, the financial uncertainty facing his presidency made itself felt. The Dow Jones Industrial Average fell 4%, its worst inauguration-day performance in history, amid fresh signs of trouble among the nation’s banks.