Some pilgrims carried large wooden crosses as they walked down the Via Dolorosa, or Way of Sorrows, stopping at 14 stations that commemorate events that befell Jesus as he was led to his death.
Many pilgrims prayed in the ancient Church of the Holy Sepulcher, traditionally the site of Jesus' death, burial and resurrection. Some chanted hymns, while others prostrated themselves on a smooth stone slab marking the spot where Jesus' body was placed after being removed from the cross.
The crowd in one of the Old City's streets included two dozen members of an American church group from Ohio, dressed in white. Eileen Joiner, 43, from Akron, Ohio, said she was moved to be in Jerusalem. "You see a picture and it looks impressive. You see it in person and it's always so much more," she said.
The group's pastor, Janice Skeen, said a recent shooting attack in Jerusalem hadn't deterred them. "You can't escape the feeling and the presence of God here. This is his special land," she said.
The March 6 attack by a Palestinian gunman killed eight young students at a Jewish seminary in the city.
Police said thousands of security personnel were deployed around Jerusalem because of Good Friday and the Jewish festival of Purim, which also falls this weekend. Jews celebrate Purim by dressing up in costumes and reading the Book of Esther, which recounts a victory by the Jews over their enemies in ancient Persia.
At a Purim celebration just outside the walls of the Old City, hundreds of Jewish children dressed up as angels, superheroes and rabbits were entertained by jugglers and clowns.
Police are also on high alert because of fears of a revenge attack for the February assassination of a high-ranking commander in the Lebanese militant group Hezbollah. Israel denied involvement, but Hezbollah threatened to avenge his death with an attack on Israeli targets. Police spokesman Micky Rosenfeld said the alert level Friday was one below the maximum.
Israel banned West Bank residents from entering Israel for fear militants might carry out attacks, but the closure also meant many Palestinian Christians couldn't make it to Jerusalem.
Samir Helou, an engineering lecturer from east Jerusalem, said there were markedly fewer local Christians in the Old City this year. "We pray every year for a better situation, and then every year becomes worse," he said.
"We pray, but God doesn't have time for us," Helou said.
Other visitors in evidence in Jerusalem hailed from Spain, Poland, the Philippines, Brazil, and several African nations, some wearing traditional costumes.
Anita Ekka, a Catholic nun from Madhya Pradesh, India, said she appealed for an end to conflict. "We pray here for the peace of the world, of the heart and of the mind," she said.
One American visitor, Linda Edwards of Perry, Georgia, said she loved the mix of nationalities but was somewhat put off by the countless vendors hawking postcards and religious trinkets.
If Jesus were here, she said, he would be "turning all the tables over and would get arrested by the police."