The cross of Saint Andrew is expected to attract as many as 400,000 pilgrims to Moscow's Christ the Savior Cathedral, where it is currently on display.
Brought from Patras, Greece, to mark the 1025th anniversary of the Russia's baptism, the cross will be on display from 5 p.m. Friday. It will then be accessible from 8 a.m. to 10 p.m. until July 25.
The city's culture department believes the largest group of visitors will come this weekend, Interfax reported Friday.
It was on display in St. Petersburg last week and drew around 200,000 worshippers in the space of a few days.
The apostle Saint Andrew holds a special place in Orthodoxy, as he preached to the eastern parts of the Roman Empire and beyond. He is one of the patron saints of Russia.
Fifty volunteers have been employed by the cathedral to help with crowd control, passing out water and providing first aid to those who need it.
Having to deal with huge numbers of visitors is not uncommon at the cathedral. In November 2011 more than 80,000 people lined up hoping to catch a glimpse of the Virgin Mary's Cincture, a belt believed to have been worn by Jesus' mother. Despite freezing temperatures, the line to see the belt stretched four metro stops from Kropotkinskaya to Vorobyovy Gory.
After Moscow the cross will travel to Ukraine and Belarus with an Orthodox delegation.