No
yes, they need
Yes, they need one.
No. Bulgaria and Ireland are both part of EU.
Yes, Americans need a visa to travel to Canada.
Yes, Americans need a visa to travel to Russia.
Yes Americans do need a visa to enter the Czech Republic.
Yes, Americans need a visa to travel to Saudi Arabia.
Yes, Americans need a visa to travel to the UK for tourism or business purposes.
Yes, Americans need a visa to travel to the Philippines for stays longer than 30 days.
Yes, Americans need a visa to travel to Germany for stays longer than 90 days. For short visits of up to 90 days, Americans can travel to Germany visa-free under the Visa Waiver Program.
yes, you can. i you have a valid romanian visa, you can stay 5 days in bulgaria if your way is to romania