Sheikh Mohammed bin Rashid and Sheikh Mohamed bin Zayed attended the opening of Al Wasl Plaza - the 'beating heart' of Expo 2020 Dubai.

They led a delegation of dignitaries at the celebratory event on Wednesday as the countdown to the spectacular world's fair continues to gather pace.

Sheikh Mohammed, Vice President and Ruler of Dubai, said the sprawling plaza will be the meeting place for the world when the event begins in October.

He said tens of thousands of employees are working tirelessly to ensure the emirate is ready for what is being billed as the 'greatest show on earth'.

Sheikh Mohammed shared footage of the grand ceremony on Twitter.

"One huge dome will be the beating heart of the Expo around which the world will meet from 192 countries. 38,000 employees continue day and night to achieve the largest global gathering in 2020. Dubai and the UAE are waiting for the world," said Sheikh Mohammed.

"We will celebrate the accomplishments of the last 50 years. Thanks to the efforts of UAE citizens and residents, as well as all those who have contributed to its success and prosperity, Expo 2020 will mark the start of new 50-year phase of leadership and achievements."

It was announced earlier this month that construction on the crown jewel of the plaza - the world’s largest 360-degree projection dome - was complete.

The steel trellis that makes up Al Wasl's dome, with sand-coloured screens, has been fitted with more than 200 projectors and is wide enough to fit two Airbus A380s.

Al Wasl – meaning connection in English – is the World’s Fair centrepiece, connecting the districts, and will host its main ceremonies.

Sheikh Mohamed bin Zayed, Crown Prince of Abu Dhabi and Deputy Supreme Commander of the Armed Forces, said Expo 2020 will be an opportunity to showcase the achievements of the Emirates with the world.

“Through Expo 2020, we will show the world how our union was the starting point for our development journey, and how our founding fathers established the robust foundations necessary for sustainable development and progress,' said Sheikh Mohamed.

"We will also have an opportunity to demonstrate how the spirit of collaboration is embedded deep in our national ethos and serves as a means for progress and development.

"The world will also be able to better understand the achievements we have accomplished in the short period since our nation’s foundation, and will learn about our traditions and heritage, our diversity and our experience of peaceful co-existence.”

The Vice President of Dubai and the Abu Dhabi Crown Prince were joined on their Expo tour by Sheikh Hamdan bin Mohammed, Crown Prince of Dubai, Sheikh Mansour bin Zayed, Deputy Prime Minister and Minister of Presidential Affairs, and other high-ranking officials.

Expo 2020 Dubai - which will run from October 20 until April 10 of next year - is set to attract 25 million visitors from across the globe.

Organisers expect 70 per cent of visitors to be drawn from outside the Emirates.