While undergoing renovation and restoration, the roof of Notre-Dame caught fire on the evening of 15 April 2019. Burning for around 15 hours, the cathedral sustained serious damage, including the destruction of the flèche (the timber spirelet over the crossing) and most of the lead-covered wooden roof above the stone vaulted ceiling. Contamination of the site and the nearby environment resulted. Following the fire, many proposals were made for modernizing the cathedral's design. However, on 29 July 2019, the French National Assembly enacted a law requiring that the restoration must preserve the cathedral's 'historic, artistic and architectural interest'. Stabilizing the structure against possible collapse was completed in November 2020, and the reconstruction began in 2021. The government of France hopes the reconstruction can be completed by Spring 2024, in time for the opening of the 2024 Summer Olympics in Paris. President Emmanuel Macron confirmed on 14 April 2021 that the cathedral site will be formally returned to the church on 15 April 2024, and the first mass will be held in the cathedral nave on that day, even if the reconstruction is not finished by then.