10 most difficult ge­og­ra­phy of Europe riddles

The Tara is a river in Montenegro and Bosnia and Herzegovina. It cuts the Tara River Canyon that is 78 kilometers long and has 1,300 meters at its deepest.

The Baltic Sea is one of the largest brackish inland seas by area, and occupies a basin formed by glacial erosion during the last few ice ages. It is about 1,600 km (990 mi) long, an average of 193 km (120 mi) wide, and an average of 55 metres (180 ft) deep. The maximum depth is 459 m (1,506 ft).The current course of the shoreline was formed about 2 thousand years ago.

Due to its altitude of 667 m (2,188 ft) above sea level, The Madrid region features a Mediterranean climate with cool winters, including sporadic snowfalls and minimum temperatures often below freezing.

Öræfajökull is the largest active volcano in the country, and on the summit crater's north-western rim is Hvannadalshnúkur, the highest peak in Iceland at 2,110 metres (6,920 ft). Geographically, Öræfajökull is considered part of Vatnajökull, and the area covered by glacier is within the boundary of Vatnajökull National Park.

Saint-Michel d'Aiguilhe is a chapel in Aiguilhe, near Le Puy-en-Velay, France. It was built in 969 on a volcanic plug 85 metres high. The chapel is reached by 268 steps carved into the rock. It was built to celebrate the return from the pilgrimage of Saint James.

This group includes 4 Nordic countries (Iceland, Norway, Sweden, Denmark) and the Czech Republic.

Iceland, having area of 103 000 km², is larger than Ireland (84 406 km²). Other European islands are much smaller.

The Danube, the second largest river in Europe (2845 km), flows into the Black Sea in Romania.

Spain officially the Kingdom of Spain , is a country mostly located on the Iberian Peninsula in Europe. Its territory also includes two archipelagoes: the Canary Islands geographically belonging to Africa and the Balearic Islands in the Mediterranean.

An estuary is a partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it, and with a free connection to the open sea. The Thames flows into the North Sea via the Thames Estuary. The other listed rivers leave its mouth via delta.