VIDEO: Celebrations across UAE mark ‘One Year’ countdown to Expo 2020

Spectacular pyrotechnics left a blazing trail on the Dubai skyline to mark the "One Year" countdown to Expo 2020.

Dubai bookmarks pathbreaking Expo 2020

Megastar Mariah Carey headlined a concert underneath the illuminated Burj Khalifa, the world's tallest building, where thousands gathered for the centrepiece of festivities across the UAE.

At exactly 20:20 local time, the skyscraper was lit up with "1 year to go" and "the world's greatest show" in both English and Arabic.

Mariah Carey performs during a concert celebrating Dubai Expo 2020 on Sunday night. AP

"These spectacular nationwide celebrations will usher in the final leg of a historic journey," said Reem Al Hashimy, Minister of State for International Cooperation and also Director General of Expo 2020.

"The next 12 months will see us put the finishing touches to ensure an exceptional World Expo."

Fireworks explode at the Burj Khalifa during an event to celebrate the Dubai Expo 2020 One Year to Go. AP

Dubai hopes to attract 15 million visitors to the sprawling site taking shape on sand dunes south of the city's gleaming downtown, being built at the staggering cost of Dhs30 billion ($8.2 billion).

Officials are pinning high hopes on the event, the logo of which is emblazoned on everything from business cards to airliners.

Some 200 countries will take part in the fair, which runs from Oct.20, 2020, to April 10, 2021.

Artistes perform at an event to celebrate the Dubai Expo 2020 One Year to Go. WAM

Attractions will include the UAE pavilion in the shape of a falcon in flight and a dome crafted from 800 tonnes of steel which will be the world's largest 360-degree projection surface.

Organisers say the Expo is much more than a six-month trade show.

The experts believe the much-anticipated event will give the economy a tremendous boost.

Mariah Carey performs during a concert celebrating Dubai Expo 2020. AP

The first "World Expo" was held at the Crystal Palace in London in 1851, world fairs have been used to showcase new ideas and technology and serving as nation-branding exercises.

Raed Safadi, chief adviser to Dubai Economy which is charged with guiding the emirate's financial fortunes, said Expo will add some $34.6 billion to the economy between 2013 — when it won the bid to host the event — and 2030.

"It will be gross value added, directly, indirectly and induced. You come to Expo, you stay at a hotel, you go shopping, etc," he said.

Also in the spotlight is the government's goal of attracting 20 million tourists in 2020, an increase of around 20 per cent from this year.