Ten stamps are being issued to mark the birth of scientist Charles Darwin in Shrewsbury exactly 200 years ago.
Royal Mail said it was celebrating the studies that inspired his theories on evolution - zoology, botany, geology, ornithology and anthropology.
Events wee being held in Shrewsbury on Thursday to mark the anniversary.
In his On The Origin of Species, published in 1859, Darwin outlined how life evolved through natural selection over millions of years.
Jigsaw-shaped stamps symbolise how his studies of different disciplines came together to form new ideas on evolution, Royal Mail said.
It has also produced a special sheet comprising four stamps illustrating the wildlife of the Galapagos Islands.
Birthday party tea
The sheet of four stamps "builds up into a contemporary map of the Galapagos Islands with key species that Darwin studied in the 1830s", Royal Mail added.
In Shrewsbury, where Darwin grew up, candles on a special birthday cake were blown out in The Square.
The cake, which was made by catering students from Radbrook College in the town, was cut on Thursday afternoon.
Other events included a Darwin Toast drink at the Morris Hall and a birthday party tea for children who were also born on 12 February.
Two plaques marking links between Darwin and a Staffordshire village were unveiled last month.
A service was held on 29 January at St Peter's church in Maer, where Darwin married his cousin Emma Wedgwood exactly 170 years earlier.