This Year's Common Christmas Tree: 50 Feet Tall, 50 Years Old

Mayor Thomas Menino and Santa Claus will flip the switch on Thursday, illuminating the city's 50-foot-high Christmas tree and a series of decorations throughout the  and . 

A total of 50 Christmas trees will dot the Common this year, according to the city's .

The 69th annual tree lighting is sponsored by the Boston Parks and Recreation Department and the Province of Nova Scotia in Canada. The ceremony starts at 6 and runs until 8 p.m. on Thursday.

This year the city's official Christmas tree -- which now stands unlit near the corner of Park and Tremont streets on the Common -- is a 50-foot-tall, 50-year-old white spruce from North Alton in Annapolis Valley, Nova Scotia.

The tree was donated by Nova Scotians Gary and Roseann Meisner. The Honourable Frank Corbett, the deputy premier of Nova Scotia, and members of the Royal Canadian Mounted Police with join Mayor Menino and Santa Claus in lighting the tree.

This is the 39th year that Nova Scotia has gifted a tree to the people of Boston as a gesture of gratitude for a helping hand extended 93 years ago. On Dec. 6, 1917 a munitions ships exploded in Halifax Harbor; Within 24 hours of the disaster Boston had loaded a train with supplies and emergency personnel that was winding its way to Nova Scotia.

Stick around until the end of the show for a pyrotechnic display underwritten by the Boston Pops. Katharine McPhee of American Idol fame, the Boston Pops Gospel Choir and the Radio City Rockettes will also be entertaining the crowd.

After the Boston Common tree lighting, Mayor Menino will head to Arlington St. in the Back Bay for for the lighting of the Commonwealth Avenue Mall. The trees along the mall will be illuminated through April 1.