The shock announcement that North Korea claimed to have carried out a hydrogen bomb test this morning sent shockwaves around the world.

South Korea has since reported that it has detected no radiation from the alleged test site.

The US Geological Survey measured unusual seismic activity, but White House National Security Council said in a statement that the US "cannot confirm these [North Korea's] claims at this time," and that it is likely to take weeks to evaluate whether a hydrogen bomb was detonated.

Here are some of the best doc's and reports from around the web to help you to understand the highly secretive North Korean state.

Channel 4 News: North Korea Uncovered: Inside the gulags

This succinct report from Channel 4's Asia Correspondent John Sparks offers a look inside Kim Jong-Il's North Korea.

It shows the state controlling media events, convert videos from black markets in the countryside and testimonies from defectors, including a harrowing account of the treatment of prisoners in the country as they face torture and are forced to clear the bodies of dead prisoners with pitchforks.

 BBC - Holidays in the Axis of Evil: North Korea

In 2003 British producer and journalist Ben Anderson endeavored to visit every country mentioned in George W Bush's 'Axis of Evil' speech - the core counties being Iran, Iraq and North Korea, while Cuba, Libya, and Syria also received honourable mentions.

The idea was to travel to these countries on tourist visas and to shoot what he saw on basic video cameras. It the case of North Korea this involved a state tour of Pyongyang while the reporter gently probes his guides to get greater insights into life inside the country.

Vice Media CEO Shane Smith later admitted that he copied Anderson's film when he made Vice's breakout online documentary the Vice Guide to North Korea (Anderson went on to become a senior producer for Vice News).

Vice - North Korean Labour Camps (2011) 

You might not be surprised to hear North Korea being accused of running labour camps, but this Vice piece investigates a more alarming claim - that the country is selling workers to work camps in Russia.

Vice co-founder and CEO Shane Smith travels deep into Siberia's forests searching for North Korean workers.

VICE on HBO: The Hermit Kingdom

As Vice has grown from a small free magazine to a billion dollar pan-media empire, North Korea has remained a subject which it has returned to time and time again.

This short doc' made as part of its news series for HBO follows Dennis Rodman and a trio of Harlem Globetrotters to Pyongyang to take part in an exhibition basketball game alongside North Korean athletes - all under the gaze of supreme leader Kim Jong-un.

The History of the North Korean Army

This piece of military propaganda produced by North Korea offers an insight into "Official North Korea" and the historical narrative that its leaders draw from.

The section after 27 minutes show soldiers being hit with wooden logs, and what seem to be sharpened blades (although they don't leave a scratch), rolling over shattered glass, and even jumping through flaming hoops.

Reaction from South Korea

Jason Strother is a journalist based in the South Korean capital, Seoul. He told Newstalk Breakfast the public there has largely ignored North Korea's claims: