Jezero is a crater

Impact crater

In the broadest sense, the term impact crater can be applied to any depression, natural or manmade, resulting from the high velocity impact of a projectile with a larger body...

 on Mars

Mars

Mars is the fourth planet from the Sun in the Solar System. The planet is named after the Roman god of war, Mars. It is often described as the "Red Planet", as the iron oxide prevalent on its surface gives it a reddish appearance...

. Once flooded with water, the crater contains a fan-delta

River delta

A delta is a landform that is formed at the mouth of a river where that river flows into an ocean, sea, estuary, lake, reservoir, flat arid area, or another river. Deltas are formed from the deposition of the sediment carried by the river as the flow leaves the mouth of the river...

 deposit rich in clay

Clay

Clay is a general term including many combinations of one or more clay minerals with traces of metal oxides and organic matter. Geologic clay deposits are mostly composed of phyllosilicate minerals containing variable amounts of water trapped in the mineral structure.- Formation :Clay minerals...

s.

In several Slavic languages

Slavic languages

The Slavic languages , a group of closely related languages of the Slavic peoples and a subgroup of Indo-European languages, have speakers in most of Eastern Europe, in much of the Balkans, in parts of Central Europe, and in the northern part of Asia.-Branches:Scholars traditionally divide Slavic...

 including Bosnian

Bosnian language

Bosnian is a South Slavic language, spoken by Bosniaks. As a standardized form of the Shtokavian dialect, it is one of the three official languages of Bosnia and Herzegovina....

, Croatian

Croatian language

Croatian is the collective name for the standard language and dialects spoken by Croats, principally in Croatia, Bosnia and Herzegovina, the Serbian province of Vojvodina and other neighbouring countries...

, Czech

Czech language

Czech is a West Slavic language with about 12 million native speakers; it is the majority language in the Czech Republic and spoken by Czechs worldwide. The language was known as Bohemian in English until the late 19th century...

, Serbian

Serbian language

Serbian is a form of Serbo-Croatian, a South Slavic language, spoken by Serbs in Serbia, Bosnia and Herzegovina, Montenegro, Croatia and neighbouring countries....

, and Slovenian, the word jezero means "lake".

Mars Science Laboratory

Jezero was one of the sites considered for exploration by the Mars Science Laboratory

Mars Science Laboratory

The Mars Science Laboratory is a National Aeronautics and Space Administration mission with the aim to land and operate a rover named Curiosity on the surface of Mars. The MSL was launched November 26, 2011, at 10:02 EST and is scheduled to land on Mars at Gale Crater between August 6 and 20, 2012...

. Clay minerals have been detected in and around the crater. The Mars Reconnaissance Orbiter identified smectite clays. Clays form in the presence of water, so this area probably once held water and maybe life in ancient times. The surface in placs are cracked into polygonal patterns. Such shapes often form when clay dries out. These patterns can be seen in the image below. The image shows a channel that carried water and seduiments into Jezero Crater.

The aim of the Mars Science Laboratory is to search for signs of ancient life. It is hoped that a later mission could then return samples from sites identified as probably containing remains of life. To safely bring the craft down, a 12 mile wide, smooth, flat circle is needed. Geologists hope to examine places where water once ponded. They would like to examine sediment layers.