What it's like inside the terrifying super-max prison where the Boston Bomber is expected to be executed

Boston bomber Dzhokhar Tsarnaev has been sentenced to death, but it may be years before he's executed because of a lengthy appeals process.

Yet when he is put to death by lethal injection, it's expected to be at the US Penitentiary in Terre Haute, Indiana.

Terre Haute is a high-security prison that houses federal death-row inmates.

The last federal execution, of Oklahoma City Bomber Timothy McVeigh, was conducted at Terre Haute in 2001.

Though US Penitentiary Terre Haute has been open since 1940, Tsarnaev would likely be held in the Communications Management Units, a special unit opened in 2006 for terrorism-related offenses.

Because of the prison's reputation for housing some of the country's biggest security threats, some have called it "Guantanamo North."

According to NPR, the units have 50 cells and house many men convicted in notable post-9/11 cases, as well as those involved in the 1993 World Trade Center bombing, the 1999 "Millennium" plot to bomb the Los Angeles International Airport, and multiple hijacking cases.

High-profile inmates at Terre Haute include John Walker Lindh, known as the "American Taliban," and Somali pirate Abdulwali Abdukhad Muse, whose hijacking was dramatized in the film "Captain Phillips."

The Communication Management Units in the prison severely restrict communications between inmates and the outside world. Inmates are limited to two two-hour nonphysical visits per month, plus one 15-minute phone call per week.

Mail must be screened, copied, and evaluated before being delivered to inmates. All conversations must be in English.

Sister Rita Clare Gerardot, who has been a spiritual adviser to death-row inmates at Terre Haute, once described the experience of death row inmates at the facility:

"They are in a small cell by themselves. All their meals are pushed through a slot. There is no recreation, but they can go out of their cells three times a week into cages," Gerardot told The Tribune-Star, a newspaper in Terre Haute.

Inmates can speak to one another from the front of their cells, according to Gerardot, and have limited time to use a phone, e-mail, or a library.

"Truthfully, I don't know how they keep their sanity. They have to be persons of great strength of will to get up every day, and know they have no choices," Gerardot said.

Though 74 people have been sentenced to death in federal cases since the 1988 reinstatement of the federal death penalty, three people have been executed.

The Boston Globe put together the details of how Tsarnaev would likely be executed. Here are some of the details from the Bureau of Prisons' "Execution Protocol":

Location: Executions are performed at the U.S. Penitentiary in Terre Haute, Indiana. A judge may choose to relocate the execution to a state where the death penalty is legal if that would be more convenient for victims and family members to access.

Last meal: Between three and 12 hours before death, those condemned to die receive a last meal of their choosing, cooked by prison staff. Alcohol is not allowed.

Clothing: The condemned individual is dressed in khaki pants, a white T-shirt, white socks, and slip-on shoes.

Method of execution: Lethal injection is the only approved method of execution for the federal government. Other options could be considered in the Justice Department's review.

Witnesses: Up to eight victims or victim's family members can watch the execution. The condemned individual can choose one spiritual advisor, two attorneys, and three family or friends to be present. They are located outside the execution room and can watch through a window.

Media: Ten members of the media are allowed to watch the final moments through a window. There are no cameras or recording devices allowed in the building.

Last words: The prisoner set to be executed is allowed to give a "reasonably brief" final statement. Those are then transcribed and given to media members.

The signal: The U.S. marshal says "We are ready." The executioner delivers the lethal drugs.

Time of death: The exact time of death is recorded, and takes place in the early morning. Jones was executed at 7:08 a.m., McVeigh at 7:14 a.m., and Garza at 7:09 a.m.

Responsibility for remains: The death row inmate is allowed to designate a person to handle disposing their body after death.