image of snow leopard. The text on the reverse side of the 200 tenge banknote is written in Kazakh, although text on the reverse sides of the other banknotes is written in Russian. 2006 series The National Bank of Kazakhstan issued a new series of tenge banknotes in 2006. This was not a currency reform as they replaced existing notes at face value. The 2006 series is far more exotic than its predecessors. The obverse is vertical and the denomination is written in Kazakh. All denominations depict the Astana/Nur-Sultan Bayterek monument, the flag of Kazakhstan, the Coat of arms, the handprint with a signature of president Nursultan Nazarbayev and fragments of the national anthem. The main differences across each denomination are only the colours, denominations and underprint patterns. On the contrast, the reverse side of the notes are more different. The denomination is written in Russian, and each denomination shows a unique building and geography of Kazakhstan in the outline of its borders. The first printing of the ₸2,000 and ₸5,000 notes issued in 2006 had misspellings of the word for "bank" (the correct spelling "" bankı was misspelled "*" banqı). The misspelling was a politically sensitive issue due to the cultural and political importance of the Kazakh language. On 3 October 2016, the ₸2,000, ₸5,000 and ₸10,000 banknotes of the 2006 series lost their legal tender status and are no longer valid. From 4 October 2016 to 3 October 2017, these notes can be exchanged without commission at any second tier bank and branches of the National Bank of Kazakhstan. 2011–2017 series The National Bank of Kazakhstan issued a new series of tenge banknotes dated 2011, 2012, 2013 and 2014 in denominations of ₸1,000, ₸2,000, ₸5,000, and ₸10,000. The designs for this series feature the "Kazakh Eli" monument on the front of the notes. On 1 December 2015, a new ₸20,000 banknote was introduced. It contains the issue date of 2013, and is a commemorative note to celebrate the 20th anniversary of the introduction of its national currency, but was not issued until 2015. In 2017, the National Bank of Kazakhstan issued a ₸500 banknote as part of this series, but has caused controversy over an image of a gull on the reverse side of the note and the image of the Moscow business center in Kazakhstan's capital of Nur-Sultan. New series with security features 2008 Since 2008, a