After a three-year diplomatic row between a Riyadh-led quartet and Qatar that veered from frosty to furious, Gulf leaders met in Saudi Arabia on Tuesday and restored relations.

Gulf Co-operation Council nations inked a “solidarity” deal, before Saudi said that the United Arab Emirates, Bahrain and Egypt were joining it in re-establishing ties with Qatar.

Here are five things to know about this year’s landmark GCC summit:

Qatari ruler Sheikh Tamim bin Hamad Al-Thani touching down in Saudi Arabia after more than three years of estrangement from his nearest neighbour was a watershed moment.

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As he descended from his personal plane, Saudi’s de facto ruler Crown Prince Mohammed bin Salman strode towards the stairs, coming to a stop at a coronavirus-safe distance away on the tarmac of Al-Ula airport.

Sheikh Tamim, who wore his trademark oversized sunglasses, touched his right hand to his heart as he descended the steps.

But on the ground the two men hesitated before Prince Mohammed went in for a hug, while a sword-wielding guard of honour watched on.

The scene was set for the whirlwind rapprochement when Kuwait’s Foreign Minister Ahmad Nasser Al-Sabah announced on Monday that Saudi would immediately open airspace, borders and waterways to Qatar.

Shortly after the bombshell announcement, drivers in Doha on the usually calm Salwa highway towards the Saudi border at Abu Samra sounded their horns and waved their arms from their car windows in celebration.

Late on Tuesday, Saudi Foreign Minister Prince Faisal bin Farhan announced a “full return of diplomatic relations.”

The summit served as a dramatic showcase for one of Saudi Arabia’s treasures, the desert city of Al-Ula, a largely unseen wonder for outsiders, dotted with pre-Islamic ruins amidst its mountains and wadis.

The leaders were whisked to the summit venue, a giant mirror-clad cube which reflects its awe-inspiring surroundings, looking more like a lair of a James Bond villain than the cultural venue it is.

Al-Ula was off limits to most travellers until Saudi Arabia opened to tourism in late 2019, only to shut again months later during the coronavirus pandemic.

The area is home to the kingdom’s first UNESCO World Heritage Site, Madian Saleh, built more than 2,000 years ago by the Nabataeans, who also constructed the better known Petra complex in Jordan.

The choice of the venue was carefully calculated — tourism is one of the jewels in Saudi Crown Prince Mohammed bin Salman’s vision to remake the kingdom’s economy and reduce its dependency on oil.

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The United Arab Emirates, one of the blockading countries, had been seen as a reluctant participant in the rapprochement process.

However Minister of State for Foreign Affairs Anwar Gargash became poetic after the signing.

“From the Hall of Mirrors in Al-Ula, begins a bright new page,” he tweeted.

Saudi commentators appeared on Doha-based broadcaster Al Jazeera for the first time in years, and a major Saudi media group deleted the song “Teach Qatar” — which details its supposed failings — from its YouTube channel.

“It is amusing to see so many analysts and journalists try to pour cold water over this important development,” tweeted author and commentator Ali Shihabi.

“Understandable since the gravy train of funding for many of them will likely end. A whole industry had emerged to take advantage of this split and that will dry up.”

Travel between Qatar and Saudi Arabia as well as the other ex-boycotting nations is now possible, on paper at least.

But the coronavirus pandemic will complicate any travel or trade between the nations initially.

Qatar currently requires all arrivals to have pre-authorisation before embarking, with the process taking months in some cases, and all new arrivals are subject to strict quarantine measures.

Saudi also imposes its own rules on international arrivals.

Hard-pressed Qatari hoteliers will be hoping travel can resume unhindered as the hospitality industry, which once relied on well-heeled Saudis taking holidays and long weekends over the border, looks to overcome the pandemic driven downturn.