The two 44c stamps are from 2007 Beautiful Holland series. The upper one shows Martini Tower in Groningen and the lower one shows the Dom Tower in Utrecht.
Groningen is the capital city of the province of Groningen in the Netherlands. With a population of 185,000, it is by far the largest city in the north of the Netherlands. Groningen is a university city, inhabited on average by about 50,000 students.
Martini Tower is the highest church tower in Groningen . The tower is located at the north-western corner of the Grote Markt (Main Square), is part of the Martinikerk (Martini Church). The carillon within the tower contains 62 bells. The citizens of Groningen call their tower d'Olle Grieze, meaning the old grey one in the local dialect. It is considered one of the main tourist attractions of Groningen and offers a great view over the city and surrounding area.
Utrecht is the capital and most populous city of the Dutch province of Utrecht. It is located in the eastern end of the Randstad, and is the fourth largest city of the Netherlands, with a population of 300,030 in 2007. The smaller Utrecht agglomeration including adjacent suburbs and annexed towns is home to some 640,000 registered inhabitants, while the larger region contains up to 820,000 inhabitants.
The Dom Tower of Utrecht is the tallest church tower in the Netherlands, at 112.5 metres (368 feet) in height, and the Gothic-style tower is the symbol of the city. The tower was part of the Cathedral of Saint Martin, Utrecht, also known as Dom Church, and was built between 1321 and 1382, to a design by John of Hainaut. The cathedral was never fully completed due to lack of money. Since the unfinished nave collapsed in 1674 the Dom tower became a free standing tower.