Scenes of unspeakable tragedy unfolded Wednesday afternoon at Lisabona, when the historic cable car Elevador da Gloria derailed and crashed on a central hill in the Portuguese capital, killing 15 people and injuring 18 others.

The accident occurred shortly after 6 pm, rush hour for the cable car, a popular attraction for tourists. According to Portugal’s National Institute of Emergency Medical Services, five of the injured are being treated in serious condition, with a child among them. It was reported that there are several foreigners among the injured, but their nationalities have not been specified.

The cable car with its distinctive yellow and white livery winds up and down the steep hill connecting the S Restauradores square with the Bairro Alto district, known for its nightlife. The carriage ended up overturned in the narrow alley of its route, with its sides and roof crushed. According to eyewitnesses, the cable car was descending uncontrollably and crashed hard into a building at the bend in the road.

“It struck the building with terrifying force and came apart like a cardboard box…” described the scene to the Portuguese network SIC by an eyewitness, Teresa d’Avo, referring to a vehicle that seemed to be moving without brakes. Other witnesses said the cable car crashed into a pedestrian, while panic scenes prevailed on the central avenue Avenida da Liberdade, with passers-by running for their lives.

Videos posted on social media minutes after the crash show smoke blanketing the area as passengers are evacuated from another cable car that was in front of the one that crashed. Dozens of rescuers rushed to the scene of the tragedy and completed the evacuation of all passengers in about two hours.

Operating company Carris said scheduled maintenance had been carried out on the cable car and expressed its condolences to the families of the victims. The Lisbon municipality suspended the operation of other cable cars in the city, ordering immediate controls. The SITRA trade union made it known that one of its members was among the dead.

“It is a tragedy we have never seen before,” said the city’s mayor, Carlos Moeda, while Portuguese President Marcello Rebelo de Souza expressed his condolences to the families of the victims.

The Elevador da Gloria, which was put into service in 1885 and is a designated national monument, can carry more than 40 passengers and is an integral part of the Lisbon skyline. Last year alone, the city welcomed some 8.5 million tourists, with the historic cable car attracting crowds of visitors every day.

Authorities have launched an investigation into the cause of the crash, considered the worst in the modern history of the Portuguese capital.