Syttende Mai is Norway's Independence Day. Even if you are not of Norwegian descent, Minnesota's history wouldn't be the same without the influence of Scandinavian settlers, so all Minnesotans - not just those of Norwegian descent - may join in. The Sons of Norway are hosting events to celebrate the day.

Syttende Mai is traditionally family-orientated, and celebrates and shares Norwegian culture with others. On Saturday 18, a church service precedes a flag parade, music, singing and folk dancing at the Mindekirken Norwegian Lutheran Church in Minneapolis.

Out of all the museums in the Twin Cities, I think this one is one of the most interesting. The Jackson Street Roundhouse, restored by the Minnesota Transportation Museum, is a turn-of-the-century railroad roundhouse restored by a team of volunteers. It now houses a collection of vintage trains and railroad memorabilia. There's plenty of hands-on displays for children to experiment with, and plenty of trains. The museum houses everything from 1970s models, going all the way back to the first locomotives to steam across the Midwest.

In the early days of American history towns lived or died on their links to the rest of the world, and in the last century, that meant one thing: the railroad. For a place as far from the coasts and other major cities as Minneapolis and St. Paul, the railroads were vital to survival.

I visited the museum with my son, who was fascinated by the trains, and it was enjoyable seeing the amount of love and care that has gone into restoring this place. Clearly this museum will interest train fans, but for anyone with an interest in the history of Minnesota, this museum makes a fascinating morning or afternoon out.

• The Jackson Street Roundhouse

The most hyped exhibit of the year is opening at the Science Museum of Minnesota on June 13. Star Wars: Where Science Meets Imagination was developed in collaboration with Lucasfilm Ltd and features real costumes (including Darth Vader, right) models and props from all six Star Wars films.

Interactive displays will explore real-life examples of robots and transportation inspired by Star Wars, and visitors will be invited to build their own robots and run a magnetic levitation train.

It's expected to be one of the most popular things to do this summer: admissions will be timed, and there is an extra admission charge for the exhibit. Reservations are strongly recommended, and tickets go on sale on May 21.

• The Science Museum of Minnesota

_{Photo © Lucasfilm Ltd.}

An small poll of my fellow Twin Cities drivers indicates that a lot of motorists don't know what those little white lights mounted on traffic signals are. The most common thought is that they are something to do with catching people who drive through a red light.

They are actually part of a system called OptiCom, developed by St. Paul technology company 3M, which changes the signal priorities for emergency vehicles. Fire trucks and other emergency vehicles carry a transmitter that notifies the traffic signals of their approach, and the signals change to give the emergency vehicle the right of way. The white lights come on or flash to warn drivers that the signals are about to change, and that they may need to move out of the way.

A white light means that the emergency vehicle is on the same road as you. A flashing light means that the emergency vehicle is on the road crossing yours. The signal will soon change to give the emergency vehicle the right of way. If you will be in the way of the emergency vehicle, pull safely to the side of the road, without blocking the intersection, and let the emergency vehicle pass.

Here's a more detailed explanation of how the system works, and examples of what to do if you see a white light, or a flashing white light at traffic signals.