The mathematicians of ancient Greece attributed characters to numbers and awarded some of the status of perfection. For Euclid, one of the finding fathers of modern mathematics, a perfect number was one that equaled the sum of its own divisors – that is numbers that will divide into it without leaving a remainder. The first perfect number is 6: its divisors are 1, 2, and 3, 14 which add up to 6. The second is 28 (1 + two + four + seven + 14). The Greeks knew only two other perfect: 496 and 8,128.

The Tui is one of New Zealand's most charismatic endemic birds, yet barely known outside of the country. The largest honey-eater species, the irridescent black bird, with its white 'parson tufts' at its neck can be recognised instantly through its bold antics and glorious, unique voice. Come see some fantastic photography, and listen to this bird singing, and even talking!

Alvarez had studied the work of his colleague Juan Vucetich, head of the bureau of statistics for the La Plata police. Vucetich had discovered a method of analyzing and classifying fingerprints that made them easy both to file and, equally vital, to retrieve. Until then, the police authorities had largely ignored his work. But because of the Rojas case and subsequent successes, Argentina adopted fingerprinting as its sole method of identifying criminals – the first country in the world to do so.