North Korea has regularly used anniversaries of leaders or events to build their own national narrative as well as send messages to other countries. On recent example is the use of an anniversary of the country’s founder to showcase a new intercontinental missile. Now, the country appears to be preparing for a large celebration of its 70th anniversary. Parade rehearsals, haircut patrols, and blocked visas have raised questions over what the country might be preparing to release or whom the country might be preparing to host for the event. Beyond the speculation, the event will likely contain strong messages relevant to its ongoing negotiations with the U.S., as Washington continues to work towards a denuclearized peninsula. 

Source: Signs that North Korea is planning something big for September: Blocked visas, parade practice and haircuts – The Washington Post