1926, the baseball fields did not contain backstops, and had to be vacated by July 4 of every year, so the National Guard could use the field. The cross-country running course was inaugurated in 1914. The track started out as a flat path, became hilly, turned onto a "little spell of road work," went into the forest, and crossed a water before turning back. A year later, it hosted the Metropolitan Association of the Amateur Athletic Union's Junior and Senior Cross Country championships. A modified cross-country course opened on November 5, 1921, with runners simply changing direction at the city border. The new course, which started at the original polo fields, did not conflict with either of the golf courses. In 1922, there was a proposal to acquire land for the future Saw Mill River Parkway, which would connect the park to of open space in Westchester when completed. Through the 1930s, the New York City Department of Parks and Recreation kept adding new recreational facilities in the park. The Colonial and Shakespeare Gardens had a combined 250,000 flowers by 1931, but both were demolished by the end of the decade due to bad drainage. In 1934, Robert Moses became the New York City Parks Commissioner, and during his 16-year tenure as commissioner, altered almost every aspect of the park. His job partially entailed balancing the needs of area residents, whose numbers had grown in the past decade, with transit users who traveled to the park from the north and south. Moses's development plans in the 1930s called for the construction of the Henry Hudson Parkway and Mosholu Parkway to bisect Van Cortlandt Park and meet at a trumpet interchange about half a mile north of the center, merging into the Saw Mill River Parkway. Due to objections over the construction of roads inside the park, the width of the parkways' lanes was reduced. Tibbetts Brook was dredged and landscaped in 1938 to accommodate construction. Such construction continued until 1955, during which the Major Deegan Expressway (current Interstate 87) was also built, bisecting the Mosholu Parkway. This conflicted with Moses's plans for the park as a "rural oasis", as highway construction ultimately separated the park into six pieces and demolished most of the remaining marsh in the park. This construction also induced siltation of the brook, leading to further creation of marshes. Moses also made improvements to the park itself,