In one of my favourite Cities: Lyon and the Festival of Lights

A network of lasers crisscrosses the inner courtyard of Lyon's town hall, and a multi-colored, glowing garden of almost 50 gigantic flowers is perched on the local mountain. The facades of the Church of Saint Nizier on the peninsula have been brought to life using projections and soundtracks, and even the town's landmark, the Basilica of Notre-Dame de Fourvière, has been lit up by a range of lighting effects that pulsate in time to the chimes of its church bells.

Each year, beginning on Dec. 8, this city in eastern France celebrates its four-day "Festival of Lights," a visual and audio spectacle that draws artists, urban planers, lighting experts and professionals who organize such events from all over the world. Some of the designs for this year have already been released.
The festival has its roots in Lyon's rich history. It pays tribute to the Virgin Mary, who is said to have spared the city from the plague in 1643. Almost 200 years later, on Dec. 8, 1852, there were plans to dedicate a statue to the Virgin Mary in a festival that would include fireworks and flares. But then a storm arrived, and the celebration was cancelled. By evening, though, the skies had miraculously cleared. The grateful citizens of Lyon set out candles in their windows to give the town a festive glow before pouring into the streets in celebration.
Today, the Festival of Lights has become a fantastical synthesis of the arts that attracts 3.5 million visitors each year. It incorporates 20 large-scale projects spread throughout the downtown area, as well as dozens of installations in all corners of the city. During the event, local design students can consort with the roughly 500 artists and engineers invited to take part in the celebration, which includes audio-visual displays, street theater and sparkling installations.

Pics from last year's fest:

Der Spiegel