Question: The Vanceboro-St. Croix Border Crossing is notable for a bombing attempt on February 2, 1915, by who?
Context: The 1915 Vanceboro international bridge bombing was an attempt to destroy the Saint Croix-Vanceboro Railway Bridge on February 2, 1915, by Imperial German spies. The Derby Line–Stanstead Border Crossing is a border crossing station on the Canada–United States border, connecting the towns of Stanstead, Quebec and Derby Line, Vermont.  It connects Main Street (United States Route 5) in Derby Line with Quebec Route 143 in Stanstead.  It is one of two local crossings between the two towns (the other is the Beebe Plain-Beebe Border Crossing), which historically had many more.  This was a major crossing point until the construction of Interstate 91 and the Derby Line–Rock Island Border Crossing in the 1970s.  The historic 1930s United States station facilities were listed on the National Register of Historic Places in 2014.  Both stations are open 24 hours per day. The Orient – Fosterville Border Crossing is an international border crossing between the towns of Orient, Maine, United States and Fosterville, New Brunswick, Canada on the Canada–US border.  At this crossing, the United States is still operating the original border station built in 1936, which was listed on the National Register of Historic Places in 2014.  Canada built its current border station in 1986.  This part of the border is at the St. Croix River, which is little more than a stream here.  The original bridge connecting Orient with Fosterville was said to be the shortest international bridge between the US and Canada. The Armstrong–Jackman Border Crossing is a border crossing on the Canada–United States border, located southeast of Saint-Théophile, Quebec and northwest of Jackman, Maine.  The border crossing is the northern terminus of U.S. Route 201, which also has the road name Old Canada Road north of Jackman, and the southern terminus of Quebec Route 173, also known as Route-du-Président-Kennedy - the existing Quebec Autoroute 73 already heads in the direction of this US/Canadian border crossing, as the closest Canadian freeway of any kind in the area. The Vanceboro - St. Croix Border Crossing connects the towns of Vanceboro, Maine and Saint Croix, New Brunswick on the Canada–United States border.  The Canadian government has at times called this crossing McAdam, named for the larger municipality east of St. Croix.  In the early 1900s, this crossing was located at the adjacent lock structure a short distance to the north.  A few hundred yards south of this crossing is also an international rail bridge which is notable for the 1915 Vanceboro international bridge bombing incident where a German spy attempted to destroy the bridge. Visa policy of Palestine refers to specific entry conditions into the Palestinian territories.  There are no visa conditions imposed on foreign nationals other than those imposed by visa policy of Israel.  Access to Jerusalem and the West Bank is controlled by the Government of Israel and access to Gaza is controlled by Hamas.  Visitors who enter via Allenby Bridge-King Hussein border crossing and make their connections to the West Bank or plans to travel to the West Bank known may be given an entry stamp that permits travel only in Palestinian Authority-controlled areas of the West Bank.  Exiting Gaza via the Erez crossing into Israel is nearly impossible.  Exit through the Rafah border crossing into Egypt is unpredictable and requires prior permission from Egyptian authorities.  The crossing often closes for extended time periods in which visitors are unable to leave Gaza Strip.  Visitors of Palestinian origin need a Palestinian passport or travel document in order to leave and may enter only via Allenby Border Crossing.  Visitors of Israeli origin are not allowed to enter via Allenby Border Crossing. The Border checkpoint Helmstedt–Marienborn (German: Grenzübergang Helmstedt-Marienborn ), named "Grenzübergangsstelle Marienborn" (GÜSt) ("border crossing Marienborn") by the German Democratic Republic (GDR), was the largest and most important border crossing on the Inner German border during the division of Germany.  Due to its geographical location, allowing for the shortest land route between West Germany and West Berlin, most transit traffic to and from West Berlin used the Helmstedt-Marienborn crossing.  Most travel routes from West Germany to East Germany and Poland also used this crossing.  The border crossing existed from 1945 to 1990 and was situated near the East German village of Marienborn at the edge of the Lappwald.  The crossing interrupted the Bundesautobahn 2 (A 2) between the junctions "Helmstedt-Ost" and "Ostingersleben". The Nasib Border Crossing (Arabic: مركز نصيب الحدودي‎ ‎ ) is an international border crossing between Syria and Jordan.  It is one of the busiest border crossings in Syria and is situated on the Damascus-Amman international highway.  It is the main crossing for Syrian exports to Jordan and the GCC countries.  In April 2015, the crossing fell to control of Free Syrian Army and al-Nusra Front during the Battle of Nasib Border Crossing. The Rafah Border Crossing (Arabic: معبر رفح‎ ‎ "Ma`bar Rafaḥ", Hebrew: מעבר רפיח‎ ‎ ) or Rafah Crossing Point is the sole crossing point between Egypt and Gaza Strip.  It is located on the Gaza–Egypt border, which was recognized by the 1979 Israel–Egypt Peace Treaty.  The original crossing point was named Rafah land port.  Only passage of persons takes place through the Rafah Border Crossing.  All traffic of goods is diverted to the Kerem Shalom border crossing. The Nitzana Border Crossing (Arabic: معبر نيتسانا‎ ‎ , Hebrew: מעבר ניצנה‎ ‎ ) is an international border crossing between El Ouga and Nitzana, Israel.  Opened in 1982, the crossing used to handle pedestrians as well as private cars but most of the crossing was being done via the Taba Border Crossing in Eilat and the Rafah Border Crossing in Rafah that the Israelis decided to shut down the crossing to tourists.  There is talk of possibly reopening the crossing to tourists now that the Rafah crossing is no longer in Israeli control.
Answer: Imperial German spies