Clara was nude while invisible. However, when her power disappears, she has clothes on.
After dipping herself in "rubber", Clara is shown to be bald. Clara was only invisible, not bald. The "rubber" should have covered her hair. Furthermore, her head was not shaved, as seen when they return to the present.
Clara is invisible, so she is dipped into "rubber" to create a fake skin for her. Fake eyeballs are then inserted into her eye sockets, even though she already has REAL eyeballs in her eye sockets! Being invisible does not make one not have eyeballs.
The movie is partially set in 1497, but Leonardo (Pietro) isn't depicted historically accurate to the time.
The movie is partially set in 1497, but people already know too much about America, which was only "discovered" five years earlier in 1492.
A woman should not wear pants during Middle Ages.
The Middle Ages ended with the fall of Constantinople in 1453. This film is partially set in 1497, which is more correctly referred to as The Renaissance.