National day of mourning: What’s open and what’s closed on Wednesday

(CNN) -- There will be a national day of mourning Wednesday to honor the late former President George H.W. Bush, who died Friday night at 94.

Friends and family will celebrate his life during a memorial service at the National Cathedral in Washington. President Trump is expected to attend along with former Presidents Barack Obama, George W. Bush, Bill Clinton and Jimmy Carter.

National days of mourning don't happen often, so you may be confused about what's open and what's not.

Here's a list of what offices and agencies will be closed to pay tribute to the 41st president:

• President Trump has issued an executive order to close the federal government. Most federal employees will be given the day off, unless they cannot be excused for national security, defense or other essential reasons.
• Some national parks may be closed or have limited services to visitors.
• The New York Stock Exchange will suspend normal trading and the Nasdaq will also close for the day.
• The US Postal Service will only make limited package deliveries and will "suspend regular mail deliveries, retail services and administrative office activity."
• The US Supreme Court has delayed arguments for the day.
• Maine Governor Paul R. LePage called President Bush "Maine's president" in an order closing executive departments in the state, where the Bush family has a summer home. "The Bush family's active participation in the Kennebunkport community has touched many lives. During his presidency, national and world leaders came to Walker's Point to address issues of national and international importance in the peaceful and beautiful setting of the Maine coast in the summer," he said.
• Texas Gov. Greg Abbott issued an executive order to close state agencies, offices and departments. President Bush will be laid to rest Thursday at his presidential library on the Texas A&M University campus, where his wife Barbara and their daughter Robin are also buried.