Last March two female suicide bombers blew themselves up on the Moscow metro, killing 40 people.

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She watched two adolescents engaged in heavy kissing on the seat across from hers, pressing themselves up against the large circle of the Moscow metro map.

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Russians, especially Muscovites, will probably have to continue to endure terrorist attacks attributed to Chechen rebels, such as the bombing of the Moscow metro in February, which killed at least 39 people.

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Moscow's Metro is one of the most-used underground railways in the world, carrying about 5.5 million passengers a day.

BBC: Moscow Metro hit by deadly suicide bombings

Luckily, Kyiv metro is nothing like Moscow's branched out forest.

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After the world nukes itself into oblivion, most of Moscow is able to find salvation in the Metro system.

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Extremists from the North Caucasus have been implicated in a number of terrorist attacks within Russia, including the 2011 bombing of Moscow's Domodedovo Airport and the 2010 bombing of its metro.

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Despite its relatively central location just northwest of the Kremlin, the only way to get to the complex is either by infrequent metro service on a newly built line, or via narrow off ramps from Moscow's busiest ring road that often are clogged by construction vehicles.

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After a series of suicide bombings in Moscow and elsewhere over the past year, it was perhaps a matter of time before the metro was hit.

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The Christmas Eve service in Moscow's Christ the Saviour began at 2200 local time, and the city's metro laid on special trains to allow the many worshippers to return home late.

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