On 17th and Montgomery in North Philly (3 blocks west of Temple) lies the Wagner Free Institute of Science...it was founded in the 1850's as a free school for physical sciences...when Seymour Wagner (partron and founder) died in the early 1900's, he basically left his estate to carry it on...mostly family members...and pretty much nothing has changed since then...today, when you go thru the doors, you are basically looking at a museum of a museum...the place looks like it has not been touched since about 1910...I think they still have free lectures there, and their collection is pretty amazing (lots of taxidermy, some dinosaur specimens...all natural sciences...)

Are there any other hidden/ little known museums people have experienced in Philly? I know the Civil War museum is another one (1805 Pine Street)...

The Wagner is in a pretty frightening area of North Philly (it was actually outside the city when it was founded) but well worth the trip...check the hours before you go...