Photo/IllutrationThe Ark Nova portable concert hall springs up in the middle of Tokyo’s bustling Roppongi district Sept. 14. (Hiroki Endo)

  • Photo/Illustraion
  • Photo/Illustraion
  • Photo/Illustraion

A gigantic purple "balloon" sprang up in central Tokyo early Sept. 14.

The hulking object is a portable concert hall designed by acclaimed Japanese architect Arata Isozaki and British sculptor Anish Kapoor.

Ark Nova in the courtyard of the trendy Tokyo Midtown complex in the capital’s Roppongi district will remain there through Oct. 4.

The venue is made out of strips of purple polyester, and is 18 meters high and 30 meters wide. About 500 people can fit inside.

From 8 a.m., workers started blowing air into the "skin" of the structure to inflate it. Ninety minutes later a giant purple monstrosity had sprung up amongst the surrounding skyscrapers.

The Ark Nova project came into being to aid recovery from the 2011 Great East Japan Earthquake and tsunami.

Between 2013 and 2015, the portable hall traveled around areas badly affected by the quake and tsunami, including Matsushima and Sendai in Miyagi Prefecture and the city of Fukushima. Music events were held inside.

During this rare appearance in Tokyo, Ark Nova will be open to the public from Sept. 20 to 24, and again on Sept. 30 and Oct. 1. The admission fee is 500 yen ($4.50). The proceeds will be donated to rebuilding efforts in disaster-stricken areas.

A concert is scheduled for Oct. 1, and a portion of ticket sales will help support future music-related programs in struggling regions.