10 most difficult 20th century riddles

Mahatma is Sanskrit for "Great Soul". It is similar in usage to the modern. The use of the term Mahatma in Jainism to denote a class of lay priests, has been noted since the 17th century. A Mahatma is someone who practices Trikaranasuddhi.

Siqueiros was one of the most important muralists of his time. Although Siqueiros and Trótskiy were initially friends, soon they grew apart due to Siqueiros' loyalty to Stalin. The painter banded with an extremist communist group and tried to assassinate Trótskiy in his own house in Mexico City.

The name implied that West Germany had not been fully de-Nazified. Before the Wall's erection, 3.5 million East Germans defected from the GDR. Between 1961 and 1989, the wall prevented almost all such emigration.

In 1990's U.S. army and marines replaced M16 Rifles with newly designed M4 Carbines which were more compact and comfortable in use.By 2015 M4 was made prime infantry rifle in U.S. weaponry.

Alexey Arkhipovich Leonov was a Soviet astronaut, general major pilot and two-time Hero of the Soviet Union. On 18 March 1965, he became the first human to conduct extra-vehicular activity, exiting the capsule during the Voskhod 2 mission for a 12-minute spacewalk.

10 out of 12 people sentenced to death were hanged on October 16, 1946. Martin Bormann was sentenced in absentia with his remains found in Berlin in 1972 and eventually dated to 2 May 1945. Hermann Göring committed suicide the night before his execution.

Following the German invasion of Denmark and Norway, the British government became increasingly concerned that Germany would soon try to establish a military presence in Iceland. After failing to persuade the Icelandic government to join the Allies, the UK invaded on the morning of 10 May 1940.

The Brutalism, is an architectural style which emerged in the mid-20th century and gained popularity in the late 1950s and 1960s. It is characterized by simple, block-like structures that often feature bare building materials. Exposed concrete is favored in construction, however some examples are primarily made of brick. Though beginning in Europe, Brutalist architecture can now be found around the world. The style has been most commonly used in the design of institutional buildings such as libraries, courts, public housing and city halls.

The tank presented in this picture is a KV-85, the last of KV series (from the surname of soviet marshal Kliment Voroshilov). As the name suggests it had a 85 mm gun. Only 148 of them were built.

Polish Armed Forces did have around 600 tanks at its disposal. Mainly tankettes TK-3 and TKS but also 7TP, Renault FT, Renault R-35, Hotchkiss H-35 and couple of prototypes.