A Christian can attend any Jewish service including Yom Kippur. However, many synagogues require a ticket for their High Holy Day services. These are purchased before the holiday. So be sure you either acquire one or attend a synagogue that does not require tickets.
I recommend that you also attempt to contact someone about proper attire. Men generally wear a suit and are required to wear some kind of kippah or hat (a symbol of reverence to God). Women typically wear long skirts or dresses, that do not have a low neckline, especially during a Yontif (holiday). Some married women also cover their hair but it depends on the type of synagogue you're planning to attend.
The Day of Atonement is Yom Kippur (Leviticus ch.23). This is the holiest day in Judaism and the day where even secular Jews attend synagogue. On Yom Kippur, Jewish people fast from all food and drinks for a complete 25hrs, starting just before sunset the previous day.
The largest services fall in the High Holy Days. Rosh Hashanna, the New Year, usually falls sometime in late September-early October. The most attended service is Yom Kippur, the Day of Atonement. It falls ten days after Rosh Hashanna.
The Yom Kippur morning services.
To find a synagogue go to www.kosherdelight.com or www.maven.co.il Rome has a Jewish quarter and one of the oldest synagogues in the country.
Only at the synagogue during services
Jewish Mexicans do Yom Kippur.
Yom Kippur
The pronounciation of yom kippur is yum-kipp-her.
It is considered by many to be the day Moses receive the second set of the ten commandments. It was also the day the Jews were granted atonement for praying to a golden calf, and therefore many Jews fast on Yom Kippur, as a day of atonement.
Yom Kippur is not a person or a country, it is a holiday. The Egyptians chose to invade Israel on Yom Kippur because of its solemnity. They expected the Israelis to be unprepared on Yom Kippur, which was indeed the case.
First, we want to make sure that you don't think that Yom Kippur is a month. Yom Kippur is a single day, in the Hebrew month of Tishrei. Elul (אלול) is the month preceding Tishrei and all the days in it, including Yom Kippur.
Near the end of the service.