When he became the leader of the Roman Catholic Church in 2005, Pope Benedict XVI succeeded arguably the most popular pope of the last century.
John Paul II's youthful appearance and dynamic speaking style won over Catholics and non-Catholics alike.
Benedict is still something of a mystery.
A comparison to John Paul might not be fair, but it's inevitable.
The men have similar ideologies.
John Paul was adamantly opposed to abortion, condemned homosexual activity, and forbid discussions of women's ordination to the priesthood. Benedict is a critic of homosexuality, same-sex marriage, euthanasia and abortion.
The similarities end there.
The two men who became pope are very different.
While John Paul was the youngest pope elected in more than a century, Benedict is one of the oldest men ever elected pope, and many Catholics view him as frail and out of touch.
John Paul was an avid traveler and a charismatic leader, drawing crowds and boosting the profile of the Catholic Church's highest leader. He broke down barriers that separated the Catholic Church from the rest of the world and won many non-Catholic admirers in the process.
Meanwhile, in Benedict's first three years as pope, he has visited only a handful of nations in an effort to to lower the profile of the person who is pope. Instead, he has worked to bring people back to the basics of faith and prayer.
Benedict has sought to improve relations with other religious groups but has generated controversy in doing so.
Most notably, he angered Muslims by quoting -- and then rebuking -- strong criticism of Islam from a 14th-century Byzantine emperor in a September 2006 lecture on faith and reason.
But Benedict has made few enemies in the United States.
A survey released in March 2008 by the Marist College Institute for Public Opinion found that Americans have a generally positive opinion of the pope and the Catholic Church.
Most hope that during his U.S. visit, Pope Benedict will address the place of spiritual values in ordinary life.
Fifty-eight percent of the 1,000 U.S. residents polled have a "favorable" or "very favorable" opinion of Benedict XVI, while 13 percent have an "unfavorable" or "very unfavorable" opinion of the Pope. Seventeen percent of the respondents claimed to have never heard of the pope.
The contrast between the two most recent popes largely stem from their vastly different backgrounds.
John Paul (aka Karol Józef Wojtyla) was born in Wadowice, Poland, on May 18, 1920. Growing up, Wojtyla (voyteewah) wanted to be an actor.
In 1938, he enrolled at Krakow's Jagiellonian University and studied drama there until 1939, when the Nazis occupied Poland and closed classes. He joined Rhapsodic Theatre and studied in a clandestine seminary.
In 1942, Wojtyla entered the underground seminary run by the Archbishop of Krakow. On Nov. 1, 1946, Wojtyla was ordained a priest.
Wojtyla was elected pope in 1978, following Pope John Paul I's death. He was the first non-Italian pope since 1523 and, at 58, the youngest pope elected since Pope Pius IX in 1846.
John Paul II traveled extensively during his pontificate, logging more than 725,000 miles to 117 countries, including Poland, the Holy Land, Japan, South Korea, Puerto Rico, Egypt, Cuba and the United States.
He consistently attracted large crowds on his travels.
He was the first reigning pope to travel to the United Kingdom, the first Catholic pope to visit and pray in an Islamic mosque, and the first pope to visit the Nazi Auschwitz concentration camp in Poland.
Benedict (aka Joseph Alois Ratzinger) was born on April 16, 1927, in Marktl am Inn, Bavaria, Germany.
Ratzinger was 6 years old when the Nazis came to power in Germany and was required to join the Hitler Youth in 1941 after he turned 14.
He was also in the seminary at the time.
In 1943, Ratzinger was drafted into the German anti-aircraft corps at 16; he deserted two years later.
In November 1945, he re-entered the seminary with his brother Georg.
The two were ordained on June 29, 1951.
Ratzinger became a well-known Roman Catholic theologian and author.
Before his election as pope and while serving as prefect of the Congregation for the Doctrine of the Faith, he repeatedly said he wanted to retire and continue writing books.
Ratzinger was 78 when elected to succeed John Paul II in 2005.
He's the first German pope in almost 1,000 years and the oldest person to have been elected pope since Pope Clement XII in 1769.