Responsibility for the deadly attacks in Barcelona was claimed by entities said to represent Daesh. During the first attack, a young man plowed a van into people strolling on the city's famous Las Ramblas boulevard, killing 16 and injuring over 130.
The second vehicular terrorist attack, just a few hours later in the coastal Spanish town of Cambrils, was committed by a group of five terrorists and resulted in one fatality.
Recent investigations reveal that those responsible the recent killings were planning attacks on a much larger scale, but mistakenly blew up a house in Alcanar in which they had stored explosives and gas tanks.
Among the peaceful marchers were included emergency workers, police, taxi drivers and residents who carried banners reading "No Tinc Por" ("I'm not afraid"), as a public and civil denunciation of violence, according to CBS News.
The reigning Spanish monarch, King Felipe VI, as well as Prime Minister Mariano Rajoy, also marched in the public demonstration as a show of support and unity.
Central, regional and local authorities joined, even though authorities have been heavily criticized following the attacks for not sharing vital intelligence between law enforcement agencies that could have been used to prevent the deadly attacks.
Many members of the local Muslim community also joined in Saturday's peaceful march, condemning violence in the name of religious belief.