In the United States alone, there’s at least $70 million in fake currency floating around. Fortunately as the technology counterfeiters use improves, so does that of the bills. Color-changing ink, special polymers and holographs are just some of the innovative technologies incorporated into today’s banknotes. In 2007, the International Association of Currency Affairs picked the best new counterfeiting technologies and tactics.

Launch the gallery for a look at the inaugural winner and a few other innovative currencies.

10,000 Tenge, Kazakhstan

Judged Best New Bank Note, this bill is the first to use a security thread that is visible on both sides. The thread has distinctive markings and is transparent, so additional security features underneath are clearly visible.

50 Pesos, Mexico

A runner-up for best new bank note, this bill is made of layered plastic polymer that changes colors as the bill is tilted—nearly impossible to replicate with home equipment. A transparent window makes it even harder to fake.

1,000 Kronor, Sweden

Another runner-up for best new bank note, the 1,000 Kronor incorporates unique watermarks and is the first note to use the microlens strip, similar to the one that will be implemented in the new US $100.

10 Dollars, Hong Kong

Raised ink, such as the lettering seen in this close-up, gives this bill a distinctive texture. Elsewhere, images of a horse printed on both sides of the bill line up perfectly. Both features are difficult to fake with home equipment.

10 Rupees, Nepal

Nepal’s 10-rupee note includes a clear polymer window—difficult or impossible to replicate with regular paper stock—and thin metallic threads blended into the paper.

1,000 Dinars, Iraq

Bills include raised lettering to give the bills a distinctive texture and are printed with inks that are only visible under ultraviolet light.

20 Pounds, United Kingdom

The newest British 20-pound notes include a prominent holographic strip. The image on the strip alternates between a pound symbol and the figure “20” when the bill is tilted.