President Obama's extensive motorcade in Ottawa included 'The Beast'

It seemed to never end: a procession of sleek, black vehicles snaking its way through the capital shutting down roads and delaying traffic for the security of U.S. President Barack Obama.

The extensive motorcade that led Obama from the Ottawa International Airport on Wednesday morning included two identical black, armoured presidential limousines to confuse attackers, a Secret Service cellphone-jamming SUV to prevent remote detonation of roadside bombs, and two ambulances.

The limo that carries the president is nicknamed "The Beast" for its defences, but what makes up those defences isa closely guarded secret.

In some of the other cars were Obama's staff and members of his cabinet, including Secretary of State John Kerry and his national security advisor Susan Rice.

Two waves of police officers on motorcycles led the path to the National Gallery of Canada on Wednesday morning, ahead of a 38-vehicle procession with choppers overhead.

The motorcade, aside from the Ottawa vehicles, was flown in on two planes ahead of the president's arrival. Snipers set up on roofs at the airport before Air Force One arrived at Hangar 11 at 10:15 a.m.

The RCMP only authorizes police-led, controlled motorcades for security purposes for four people: the prime minister, the U.S. president, the Israeli president, and the pope, according to November 2015 documents from the Department of Foreign Affairs, Trade and Development obtained by CBC News in an access to information request.

TheRCMP was not available for comment on Thursday.

Police motorcade escorts can also be issued for diplomatic reasonsas an international norm to minimize delays, according to the documents.That falls under the purview of the Department of Global Affairs (formerly theDepartment of Foreign Affairs, Trade and Development).

"There are several factors or circumstances under which a motorcade escort would be requested including international practice, reciprocity, past visits (precedence) and logistical implications (timeliness and mobility of ground transportation impact the effective delivery of a program)," Global Affairs spokesperson JessicaSguintold CBC News in an email.