The existing structures, both in Lisbon and in Portugal alike, either had limited capacity (up to 4,000 people), or were difficult to adapt to non-conventional events, such as world class indoor sports competitions.

Another shortcoming of existing venues was the lack of technical infrastructure deemed necessary to host modern concerts, musicals and to allow for proper live TV coverage.

As a consequence, Portugal would not host games of important indoor sports championships and no major concerts would take place in the country in periods of cold and rainy weather.

SOM has been awarded first prize in the contests for the Olympic stadiums of Manchester and Berlin, and is responsible for designing many big sporting pavilions in the US (Portland, Philadelphia, Oakland and Minneapolis).

The main goals of the design were: 1) Minimise the visual impact generated from such a big structure; 2) rational energy use; and 3) simplify the flow of spectators in and out of the building.

By placing the main floor 6.4 metres below ground level the architects allowed for a generously high roof, while at the same time reducing the external footprint and minimizing heat exchange (as a result of the smaller surface area exposed to the weather).

As such, during the 132 days of the exposition, the Pavilion was an open space to showcase works of imagination, reflecting the fears, myths and legends that throughout history, have been associated with the World's oceans.

Written by François I. Confine and Philippe Genty, and produced by Rozon, the show (which was presented four times a day) mixed classic theatrical elements and modern multimedia technology.

Congrave cited the local startup scene and a "cosmopolitan city with better infrastructure conditions and a larger number of hotel rooms" for the decision.

The three-day event held from 7 to 10 November at the MEO Arena, site of Expo '98, drew 53,056 attendees from more than 150 countries and more than 1,500 start-ups spread over 21 venues.

Among the more than 600 speakers were a number of tech top executives from around the world, including John Chambers of Cisco Systems, Facebook CTO Mike Schroepfer, Twitter founder Jack Dorsey and Tesla's Elon Musk.

Also speaking at the event were prominent figures from non-tech areas, such as U2 frontman Bono, Salil Shetty of Amnesty International and Joana Coles, Editor in Chief of Cosmopolitan, as well as footballer Luís Figo and both the Portuguese President Marcelo Rebelo de Sousa and Prime Minister António Costa.

On 3 October 2018, Paddy Cosgrave and Prime Minister António Costa announced a €110 million deal for Web Summit to remain in Lisbon until 2028.

Shakira held a record, at the time, for the biggest audience at the venue, during her Oral Fixation Tour (2007), giving a completely sold-out show.

In 2022, Altice Arena staged the BLAST Premier Spring Finals 2022 for the Counter-Strike: Global Offensive (CS:GO) video game, which was won by Natus Vincere.